Attorneys for a teenager charged in the 2014 killing of a flea market employee are asking a state district judge in Lafayette to appoint a sanity commission to assess if Earl Joseph III is mentally fit enough to stand trial on first-degree murder.

In court papers filed Thursday, the attorneys question whether Joseph comprehends the charge filed by prosecutors and whether he’s capable of assisting his legal counsel in his defense.

According to the motion, “… it is unclear whether the defendant understands the charges against him and the consequences of a guilty verdict or a plea agreement.”

The motion asks Judge Patrick Michot to approve a commission consisting of a psychiatrist and a psychologist that both prosecutors and defense attorneys agree on. The commission’s findings would be weighed by Michot, who would rule on Joseph’s mental fitness.

Joseph had turned 15 one week before he allegedly shot Jockey Lot employee Michael Patin, 49, in the back in the flea market parking lot late Feb. 2, 2014. The business is off Interstate 49 in north Lafayette Parish, near Carencro.

According to information provided by the Lafayette Parish Sheriff’s Office in the days after Patin was killed, deputies and members of the Carencro Police Department were called to the Jockey Lot about an alleged thieving group of boys on flea market grounds. Before officer arrived, the boys crashed the vehicle they had arrived in and tried to run off.

Using police dogs, deputies and Carencro officers rounded up four of the juveniles who were hiding. But they missed Joseph. After police left with the other boys, he allegedly shot Patin in the back after Patin confronted him.

After interviewing the boys who were caught, detectives were able to identify Joseph and arrest him early the next day at his Lafayette home.

Thursday’s motion was the latest court document to question Joseph’s mental abilities.

Roxell Richards, one of Joseph’s attorneys, in a January document said Joseph’s family believes he may be suffering “from a serious psychological disturbance” that has been with him since childhood.

“This belief is based on his history of severe behavioral and emotional problems,” Richard wrote, that forced Joseph into the public school system’s special education classes.

Joseph, now 16, was scheduled to appear in Michot’s court Thursday for a hearing. The hearing, which was canceled, was to address other issues. One of them was whether the indictment that charged him on Feb. 4, 2014, violated Joseph’s due process rights.

Rogers argued in court papers that there should have been a hearing to decide whether Joseph’s status as a juvenile defendant should have been waived before the case went before a grand jury.

Joseph’s age prevents prosecutors from seeking the death penalty, even though the 15th Judicial District Attorney’s Office decided early in the case to try the boy as an adult; a 2005 U.S. Supreme Court ruling prevents the state from putting an offender to death if the crime occurred before he turned 18.

Another Supreme Court ruling prevents states like Louisiana from imposing automatic life sentences for those who murder before age 17. In Louisiana, adults convicted of first- or second-degree murder are automatically sentenced to life.

But the high court’s 2012 opinion in Miller v. Alabama now requires judges to hold sentencing hearings that take into account the defendant’s background and the nature of the crime. The ruling doesn’t prevent a judge from handing down a life sentence to a young killer.