Man allegedly killed two brothers before being arrested on his way to murder third sibling

A Washington man has been accused of killing his two half-brothers before he was arrested on his way to murder a third sibling.

Seth South, 23, was arrested Wednesday night, hours after deputies found his teenage brothers, Sebastian and Scotty Bass, with slit throats and in pools of blood inside their family home in Poulsbo, the Kitsap Daily News reports. 

Prosecutors have said South called 911 to report that one of his family members slit their throats, before the call went silent. 

The dispatcher said she heard fighting in the background, but then the connection continued to stay silent until law enforcement arrived on the scene, court documents say.

They then found Scotty Bass lying face down in a pool of blood with a kitchen knife nearby, and Sebastian sitting at the top of the staircase, also surrounded by blood with a handgun on a nearby table and a magazine and bullet next to it, according to documents obtained by the Kitsap Sun. 

Detectives later learned that South lived in the home with the two teenagers, but he was nowhere to be found.

Officers then proceeded to interview family members, and South's grandfather said he told him, 'You're either with me or against me' and that he killed 'the boys.'

His mother also claimed that South told her he didn't 'hurt the boys,' but her husband, Christopher Bass, alleged South told him he killed two people.

Documents also said South told a friend he was heading to Missouri to murder another sibling, KIRO reports. 

In the aftermath, authorities issued a warrant for South's arrest and an alert about his Toyota Tacoma was issued statewide.

Pierce County sheriff's deputies later found South traveling in the vehicle on State Route 310 near Bonney Lake, and officers threw stop sticks to deflate South's tires.

They were then able to get South to pull over, and took him into custody. 

Authorities noted there was blood on South's shift knob as well as the driver's seat, and bloody clothing was found in his vehicle.

After being questioned by Kitsap County detectives, law enforcement says South assaulted a detective when they tried to re-handcuff him, leaving the detective with a cut on his head.

South now faces two counts of second-degree murder, as well as an assault charge for hitting the detective.

He appeared in court on Thursday, when a judge requested South undergo a competency evaluation at Western State Hospital, KING 5 reports.

In the meantime, South remains held in jail as he faces two life terms in prison plus five years, along with $110,000 in fines.

He is due to be back in court later this month.