Thursday was day four of a high-profile murder case in Pasco County -- and the jury has now been selected.

Jury selection began Monday for Adam Matos, accused of a horrific domestic violence crime three years ago. 

The 32-year-old is accused of killing his ex-girlfriend, Megan Brown, her new boyfriend, Nicholas Leonard, and both of Brown's parents in Hudson in 2014. 

Detectives believe the possible motive was jealousy over Brown's new relationship. 

The jury of 12, with three alternates, was being sworn in Thursday afternoon.

On Monday, about 50 people who were pre-screened for possible jury placement were asked to stay for further questioning. 

"If you are chosen as a juror in this matter--if you find the defendant guilty beyond a reasonable doubt, the punishment in the State of Florida for that is either life imprisonment or death," Circuit Judge Mary Handsel said. 

Several potential jurors were dismissed Wednesday because they said they could not, under any circumstances, consider capital punishment. 

If Matos is found guilty, the 12 jurors will need to be unanimous in a recommendation for the death penalty.

The trial is expected to last at least three weeks.