Burton James Ewing Jr., a 48-year-old inmate at the Minnesota Security Hospital who stabbed his mother several times during an assault at Seven Mile Creek County Park in May 2012, has been found guilty of attempted murder. 

Ewing and his mother were in the park after Ewing was given a pass allowing him to leave the hospital unsupervised, despite trying to kill her 13 years earlier. He is also responsible for his sister's murder, but was found not guilty by reason of mental illness.

He appeared in court Sept. 9 where Judge Allison Krehbiel ruled that he was guilty of attempted murder charge and four other charges, including attempted second-degree murder, first-degree assault and two counts of second-degree assault, according to published reports

His attorneys will now likely attempt to prove that he was mentally ill at the time of the crime.

According to court records, Ewing stabbed his 69-year-old mother 23 times with a steak knife, after beating her with a bicycle seat and attacking her with a pair of barbecue tongs. 

Before he left, no one checked his backpack. Law enforcement officers later searched the bag and found scissors, a winter coat, several changes of clothing and all of Ewing's money.

An unnamed officer interviewed by licensing investigators said Ewing claimed he told Minnesota Security Hospital employees that he had been having thoughts of killing his mother in the weeks leading up to the pass. Ewing told the officer he believed his mother was the "anti-Christ."

But in the months leading up to the stabbing, Ewing showed few symptoms of mental illness, according to records reviewed by licensing investigators. He appeared to be taking psychiatric medications and trying to rebuild his relationship with his mother.

State regulators who investigated the Minnesota Security Hospital after the incident have said there is no indication the facility mishandled the incident.

If the conviction stands, Ewing could face a maximum penalty of 20 years in prison for the each of the two attempted murder charges and first degree assault charge.

The process used to determine whether or not Ewing was aware he was committing a crime when he attacked his mother could take several months. 

Reach reporter Jessica Bies at 507-931-8568 or follow her on Twitter.com @sphjessicabies

MPR reporter Madeleine Baran contributed to this report.