Alex Ross-King's mum speaks out after her tragic death at FOMO music festival

A heartbroken mother has recalled the moment she found out her daughter had gone into cardiac arrest after overdosing at a festival.

Alex Ross-King, 19, died after taking three doses of MDMA at the FOMO music festival in Parramatta in January 2019.

The teenager took one pill while onboard a party bus from her home on NSW's Central Coast and two pills when they arrived at about 12:30pm.

Alice told friends she had taken the pills before the festival instead of inside because she was afraid of being caught by police.

Roughly nine hours later, the teenager would be declared dead.

Her mother Jennie recalled the last conversation she ever had with her daughter during an emotional interview with YouTuber Jamie Zhu.

'I just said to her "honey, it's really hot, please make sure you drink plenty of water and stay cool" and she said, "yeah mum, no worries, I love you, bye",' she said.

'And that was the last time I spoke to her.'

Alice's friends, Mackenzie and Petra, also attended the festival. 

'She took one on the bus, as did I,' Mackenzie said. 

'When we got there, she had another two. Instead of taking it in, she decided to take both at the same time.'

A few hours later, Petra knew something was wrong when Alice struggled to maintain eye contact with her and began tripping over people. 

The group were spotted by a roaming medical officer who effectively dragged Alice with the help of her friends to the medical tent.

A paramedic assessed Alice and noted she had 'spontaneous and uncontrollable large muscle movements, signs consistent with serotonin toxicity'.

She had a temperature of 41C, so paramedics applied icepacks. Alice's jaw was spasming, her pulse was racing, and her breathing was short and irregular.

Alice was behaving erratically and borderline abusive - which her friends said was very out of character.

'They were obviously asking me questions about what she had taken, and that's when I started telling them everything,' Petra recalled.

Alice was rushed to Westmead Hospital, losing consciousness on the way. Doctors intubated her and she was put on a ventilator.

Ten minutes after arriving at the hospital, she went into cardiac arrest with an 'agitated' Mackenzie calling Jennie to let her know.

'I could tell there was something not right and I said "mate what's wrong? What's going on?" and he didn't know what to say or how to say it,' Jennie recalled. 

An emergency doctor got on the phone and asked if she was driving. He asked her to pull over and told her Alice had gone into cardiac arrest. 

Doctors administered large doses of adrenaline over four hours of attempted resuscitation. Eventually, the decision was made to stop mechanical CPR. 

A toxicology report found an MDMA concentration well into the lethal range. 

Petra had been standing outside the hospital when the doors opened and she saw her friends inside, staring at her and shaking their heads.

'That's when I knew, I just dropped to the floor,' she said through tears.

Jennie said Alice had been her 'only baby'. 

'What is my purpose now in life? What do I do?' she remembered thinking. 

Jennie has since been vocal about changing the law and educating young people. 

She now aims to launch a podcast to educate young people about the risks of substance use at festivals and provide parents with the knowledge they need to keep their children safe. 

'I just want young people to be armed with the information, not for parents to go "well my kids don't take drugs". Ok, that's great, but are you going to bet their life on it? Because that's what your doing,' Jennie said. 

'Alex didn't take drugs, to me she didn't take drugs. But she did.'