Four dogs who died after five-star pet sitter crammed seven animals into her tiny shed in blistering heat had rat poison in their livers

Pet dogs that died after a dog sitter crammed them into a tiny shed on an 86-degree night were exposed to rat poison.

Gabriela Masak had a five-star rating on dog-sitting app Rover from more than 900 reviews when the now-heartbroken owners entrusted their beloved pets to her. 

Instead, the seven owners received panicked texts about 5 am on June 29 telling them their dogs suffered heatstroke and were being rushed to a vet in Houston.

Four of the seven dogs died, and the other three were in critical condition when they got to the vet, but have since recovered. 

Masak wrote in the texts shared with DailyMail.com by the pet owners that she put the dogs to bed at 10 pm and woke up at 5 am to find her air conditioning had failed, which she blamed for their deaths.

The pet sitter was under investigated by Houston Police Department animal cruelty detectives after the dogs' deaths, but has not been charged with a crime.

Owners of at least two of the dogs that died had autopsies conducted on them, and found traces of rat poison in their livers.

Neither dog had enough of in their system to be the cause of death, but the finding was further evidence the beloved pets were not kept in a safe environment. 

Jessica Hayward, whose Petit Brabançon, a type of Brussels Griffon, named Goose died, said she was shocked by the toxicology report.

The report by a pathologist at Texas A&M Veterinary Medical Diagnostic Laboratory found 15.5 nanograms per gram of chlorophacinone, used in rodent poison.

Vets at Gulf Coast Veterinary Specialists said the concentration wasn't enough to kill Goose, and heatstroke was still the presumed cause of death.

'The anticoagulant add on test detected low levels (15.5 ng/g) of Chlorophacinone in Goose's liver,' they wrote in an email.

'This low level indicates exposure but according to the pathologist this level would not be likely to be the cause of Goose's passing. 

'In his experience, dogs that pass from anti-coagulant rodenticide toxicity normally have levels >100 ng/dl which is well above the detected level for Goose. 

'The presumption that his passing was caused from heat related illness still applies.'

Matthew Johnston, whose chocolate Labrador named Porter died, said similar levels of rat poison were detected during his pet's autopsy.

Goose's report also pointed to heatstroke, due to internal hemorrhages but was careful to say that couldn't be concluded from the pathologist's analysis alone.

'If there is clinical and circumstantial evidence to support it, the described changes can be compatible with heat stroke,' it read.

'However, as these are non-specific changes other causes of shock or disseminated intravascular coagulation cannot be ruled out.

'Unfortunately, heat stroke often does not result in pathognomonic postmortem lesions. Diagnosis is often circumstantial, relying on knowledge of ambient temperature at the time of death.'

The 86F air temperature, which would have been higher inside the shed, added to the clinical evidence, and Masak herself attributed the dogs' death to heatstroke.

A report from BARC, the City of Houston's municipal animal shelter and regulator, obtained by DailyMail.com, detailed how Masak and her boyfriend Ryan Hilton refused to speak with investigators.

A BARC officer visited the house on Clovis Road in Houston at 9:56 pm on July 1 to follow up on the reports of the dead dogs and that more were inside.

Hilton, an engineer at Chevron, answered the door and 'showed me a document their lawyer drew up and stated that they weren’t talking to any kind of law enforcement'.

'I asked for a Texas driver's license or ID and was met by Mr. Hilton slamming the door in my face,' the report continued.

The officer instead asked a neighbor if he could come into the backyard and take photos over the fence, and got several snaps of the shed.

His supervisors then asked him to check if the couple had a commercial pet license and returned to the front door.

'[Hilton] spoke only through the ring camera and stated they wouldn’t give any statements,' the report read.

The officer wrote them a commercial pet service facility license required citation and left it attached to the front door, then left.

The Houston District Attorney's Office is deliberating whether to charge Masak and Hilton with animal cruelty, or any other crimes.

Masak's Rover profile was then taken down, along with all her and Hilton's social media profiles, and she stopped responding to texts.

Multiple attempts by DailyMail.com to reach either of them were unsuccessful.

The couple even convinced Google to put a blanket blur over their entire property from all sides on Google Maps, including the shed where the dogs were kept. 

Several of the owners said they were led to believe their pet was the only one she was looking after, besides her own two dogs.

Some were repeat customers and often sent photos of their pets inside the house either by themselves or playing with Masak's dogs.

They now say they feel conned after discovering Masak had at least 11 dogs at her home in Timbergrove.

'We were lied to and deceived, we thought he was safe her house… we thought we had checked everything out, it's shocking,' Matthew Johnston, whose chocolate Labrador named Porter died, told DailyMail.com.

A small wooden shed is visible over the back fence of Masak's home that she shares with Hilton, and was only built last year when turf was put down in the backyard.

The house was pelted with eggs days after the dogs died as angry locals and friends of the pet owners shared their accusations online. 

The seven dogs, all from Rover, that suffered from heatstroke were housed overnight in the shed when its air-conditioning failed while Masak was asleep in the house, owners said police told them of Masak's account to officials. 

Meanwhile, the owners of another four dogs that were unharmed are believed to have found Masak through other channels.

Masak runs two dog-sitting businesses named Best in Class and The Ultimate Petsitter.

She studied petroleum and natural gas engineering at Pennsylvania State University where she also worked as a pet sitter in her spare time.

'Dog, cats, donkeys - you name it! I take the experience that I have from owning my own pets and apply it to this part of my business,' she wrote on her website.

A blog post from February 28, 2016, talked up her experience working in a barn and railed against pet owners who don't get their animals neutered.

'Owning a pet does not necessarily mean making sure that they are fed and cared for,' she concluded.

'You cannot control and plan for everything that will occur over the lifespan of the pet, and fixing an animal is the responsible thing to do.'

After her panicked early-morning texts and phone calls, Masak took the seven dogs to Gulf Coast Veterinary Specialists where she gave false names and contact numbers for their owners, the owners have claimed.

Jessica Hayward and Taylor Friesenhahn dropped off Goose, their Petit Brabançon, a type of Brussels Griffon, at Masak's home on June 27 and went on vacation.

Hayward said they got a call at 5:30 am on June 29 and 'immediately knew something was wrong.'

'Gabriela was crying hysterically and couldn't get words out. All I said was, "Is Goose alive?" and she said no,' she told DailyMail.com.

'We asked what happened, and she said that she put him in his crate at 10 pm and when she checked on him at 5am he was dead, and mentioned that she had AC issues.'

The temperature in Houston was between 83 and 86 degrees during those hours, and reached a maximum of 95 the afternoon before.

'An hour went by, and we hadn't heard from her, and we were hysterical so we called the vet,' Hayward said.

That was the first time the couple learned their dog was one of seven staying at the house who had been brought in with heatstroke.

'We knew nothing about the shed, nor that there were other dogs there. We were always under the impression that he was the only dog she was taking,' Hayward said.

'We never heard from her since, she still has his belongings, and there was no apology or recognition, nothing.

'We're devastated and not sure how we can even function without him. We don't have children so he wasn't just a dog, he was our child. 

'Everyone who met him knew how much we dedicated our lives to giving him the best life a dog could have. Everyone falls in love with him immediately.'

Friesenhahn said they used Masak's services a few times over the past year, but she never let them inside and always picked up or handed back Goose in the driveway.

'They created an illegal system in their home… we all feel like we've been conned and misled in the same way,' he claimed.

'How many times, we don't know, but all signs suggest there was a scaling of this operation recently.'

Matthew and Jordan Johnson lost their six-year-old chocolate Labrador named Porter and had an eerily similar story.

They were in Canada visiting the rest of their family when they got messages from Masak early in the morning about the situation.

'We had an emergency. I'm at the vet. I woke up, and the AC wasn't working,' she wrote through the Rover app in messages obtained by DailyMail.com.

'Oh no! Can we call you? Is Porter ok?' they replied, then spoke to her on the phone.

'She told us he died from heatstroke and that didn't make sense as how could it possibly have gotten hot enough in her house even if the AC went out for that to happen,' Jordan said. 

Not until they spoke with the vet did they know Porter was only one of many dogs staying together, contrary to photos Masak sent them.

'The first time we knew there were other dogs was when the vet called us and said, "You're one of the seven,"' Jordan said.

'I thought Porter was there alone with one or two other dogs. I thought I was sending my dog to [what was portrayed in] the photos she sent me. Nobody would send their dog to be in a shed with 10 other dogs.

'She called us because she needed us to call the vet and put our paperwork in and credit card down, I have no illusions that she called us because she was trying to inform us of anything because after that we heard nothing.'

The couple are still in Canada with two and four-year-old kids and all their extended family as they didn't want to take them back to the Houston heat after Porter's sudden death, so they are staying until July 14.

'It helps to be with family, but we're angry and really upset,' Jordan said.

'He was a part of our family, he's been with us through a lot of change in our lives - we got him when it was just my husband and I and were living in Calgary, and since then we've gotten married and had two kids and moved to Houston.'

Archie, an 11-month-old Bernedoodle, was luckier as he survived the night in critical condition and eventually recovered.

His owner, Andrew Seerden said he woke up to messages from Masak starting at 5:39 am.

'I'm taking Archie to the emergency room. I woke up and the AC wasn't running. He has heat stroke and we are rushing to Gulf Coast,' they read.

Seerden replied at 6:46 am, writing, 'Oh my god. Updates?' Masak wrote she was at the vet, and he asked, 'Where was he?'

Seerden said Masak didn't answer the question and replied, 'They are trying to reach you to start care.'

'We need to know what happened and where he was,' Seerden insisted. 'You need to call us back now.'

'My first thought was where was he? If our power goers out in the middle of the night we're going to get a little warm but none of us are going to get heatstroke,' he said of the brief call.

'Her response was "in the back room" – which sounds to me like it's a room, not the back shed. None of us would have been OK with them being out there.'

Seerden said the vet had problems contacting or even identifying the dogs' owners after Masak dropped them off, and only got his number because it was written on Archie's collar.

'Gabriela not once in a text or a call expressed any concern or sympathy or apologized, or asked how he was doing or what she could do,' he said.

Archie was at the vet hospital on oxygen and attached to a monitor with a feeding tube for weeks after his near-death experience.

'He was in about as bad a shape as he could have been, and still be alive. We had several meetings with the vets where they took us into a room and it felt like it was the end,' Seerden said.

Other former Masak clients whose dogs were not at her house that night were horrified to hear of the accusations shared on social media.

'Our jaws are on the floor as we read this. We just had our dog there last weekend. She usually sent pictures of him playing with a ball in the backyard but she was radio silent,' one wrote.

Another added: 'I left my dog with gabby at least 10 times. I've recommended her to friends and family. I am absolutely sick that this happened.'

A third wrote: 'She was our dog sitter but we luckily got him back a day before this happened… Very shocked... We've used her for the past two years and she always said our dog was the only one too.'

Another pet owner wrote that they hired Masak in the past because she had such good reviews on Rover and many repeat customers.

They explained that there were no incidents, but the reports explained a lot of minor issues.

'When we dropped her off the first time she did not take us inside the home to see the living conditions. We used her services 2-3 times and never saw the inside premises,' they wrote.

'Our dog would always have her chin and neck soaking wet, most likely because she was captive in that shed and she was chugging water to regulate her temperature.'

Their dog also each time came home with serious stomach issues where they had to seek weeks of medical attention.

Staff at the vet clinic also recalled their distress at having to treat the dogs when they arrived and deal with the four that died.

'As someone who took care of one of the dogs that arrived DOA at our hospital, the way I sobbed for an hour when I was told. He was a sweet little angel and the bestest boy,' one wrote,

Another vet worker wrote: 'Goose was the absolute cutest boy and was loved across so many departments. He was even in one of our OR techs' profile photos! 

'He made so many people happy and always put a smile on my face whenever I saw him.'

Other locals who heard about what happened wrote online that they heard dog barking in the backyard and reported it to authorities.

BARC, the City of Houston's municipal animal shelter, visited the house but wasn't allowed in until police obtained a search warrant.

Eventually, the remaining four dogs were removed from the property. 

Investigators were seen searching the house on Monday afternoon and Houston police opened an animal cruelty investigation. No charges have been filed.

BARC previously issued Masak a citation for not having a commercial pet service facility license.

Hayward said she wanted Rover to vet dog sitters better and make sure they were trained better and checked on how they look after dogs.

'We have to hold these apps accountable to make sure they don't allow unqualified people to take in 10 dogs, without anyone's knowledge, and there needs to be regulations to prevent this from happening,' she said.

Friesenhahn added: 'We're helicopter dog parents, we're very particular about who takes care of him and we did all the due diligence so if it can happen to us, it can happen to anyone.'

Rover said it was 'deeply concerned' and promised to conduct a 'thorough investigation' and cooperate with police.

'We are committed to supporting these pet parents throughout this heartbreaking ordeal, including reimbursing the families for related veterinary expenses,' it said.