RIVERSIDE  — A former minor league baseball player has been convicted of beating to death three people, including his father, with a bat at the family’s Southern California home.

Brandon Martin, 27, was found guilty of first-degree murder Thursday for the 2015 killings in Corona. Jurors will now decide whether to recommend life in prison or the death penalty. The Riverside County district attorney is seeking the death penalty.

Prosecutors said Martin used a black wooden baseball bat engraved with his name to attack his disabled father, Michael Martin, 64; his uncle, Ricky Anderson, 58; and an alarm system installer, Barry Swanson, 62.

Martin was chosen by the Tampa Bay Rays in 2011 in the first round of the Major League Baseball draft. He was the 38th overall selection and played three seasons with the Rays’ farm team before being released on March 26, 2015.

His behavior became erratic after he was drafted and he once punched his father in the face and put his mother in a headlock, the Los Angeles Times reported, citing court records and interviews with friends.

The killings occurred after Martin had been taken to a Riverside County mental health facility for evaluation after telling police that he choked his mother and threatened her with scissors, the Times reported.

He was held for two days. Immediately after his release on Sept. 17, 2015, Martin went to his family home and attacked his relatives and Swanson, who was there to install an alarm system “because the family feared Brandon Martin,” according to statement from the district attorney’s office.

Michael Martin and Swanson died at the scene. Anderson died two days later. Brandon Martin’s cousin discovered the bodies and called 911.

A day after the killings, Corona police spotted Martin in Swanson’s stolen pickup truck, leading to a chase that ended with Martin leaving the truck and running.

At one point, he broke into a home and jumped from a second-story window, then fought with a police dog before being arrested, according to the District Attorney’s office.