A former MLB prospect has been convicted in a triple murder that happened at his father’s home in Corona in 2015, the Riverside County District Attorney’s Office announced Thursday.

Brandon Willie Martin, 27, was found guilty in the first-degree murders of his 64-year-old disabled father Michael Martin, 51-year-old maternal uncle Ricky Andersen and 62-year-old Barry Swanson,  an alarm system installer who was working at the family’s home in Corona at the time of the crimes, prosecutors said in a news release.

On the evening of Sept. 17, 2015, officers with the Corona Police Department were called to the family’s home at the 1000 block of Winthrop Drive. 

When they arrived, officers found that the three men had been beaten to death with a black wooden baseball bat engraved with Brandon Martin’s name. Their bodies were discovered by the defendant’s cousin, who called 911, prosecutors said.

The defendant’s father and Swanson died at the scene, but Andersen lingered in a coma for two days before dying from his injuries, KTLA previously reported.

The attack occurred shortly after the defendant was released from a psychiatric care facility in Riverside where he had been held for two days for a mental health evaluation after making threats against his disabled father, officials said.

Swanson was at the home to install a security system because family members were concerned about what might happen when Martin left the facility, a neighbor previously told KTLA.

After Brandon Martin was released from the facility on the night of the murders, he went straight to his father’s house, arriving shortly after 6 p.m., authorities said.

The defendant grabbed a baseball bat inside the house and went on a rampage, pummeling all three men. After attacking the victims, Martin stole Swanson’s Ford Raptor pickup and hid out overnight.

The next day, Corona police spotted the pickup and Martin led them on a pursuit in Corona. He eventually bailed out of the truck and fled on foot, officials said in a news release.

In his attempt to evade officers, Martin broke into a home where a woman was taking a shower, officials said. The defendant tried to escape by jumping from a second-story window but encountered a K-9 officer and his dog, which led to a brief struggle before he was arrested, prosecutors said. The woman at the home was not injured.

After deliberating less than a day, a Riverside jury on Wednesday convicted Martin of the murder counts, found true a special circumstance allegation of taking multiple lives in the same crime, and further convicted him of one count each of auto theft, evading arrest, obstructing a peace officer and injuring a police canine.

The penalty phase of the trial is scheduled to begin Monday, Nov. 9, when the jury will ultimately decide whether Martin should be sentenced to death or life in prison without the possibility of parole.

Martin was chosen by the Tampa Bay Rays as the 38th overall pick in the 2011 Major League Baseball draft, officials said. He was released by the team in March 2015.

Correction: This story previously contained a misspelling of Andersen’s last name. The post has been updated.