Dustin Briggs is accused of murdering two sheriff's deputies.
After attorneys gave their opening arguments to the jury, the first witnesses were called to the stand.
The jury listened to opening arguments for more than two hours Monday morning.
Monday afternoon, they heard from the first witness, and saw some of graphic photos of the dead deputies.
Dustin Briggs of Gillett walked into the Bradford County Courthouse for the first day of his capital murder trial.
He didn't show much response during opening arguments, or when the jury saw pictures of deputies Michael Van Kuren and Christopher Burgert lying dead on at the Brigg's family home in Gillet.
Senior Deputy State Attorney General Pat Blessington is prosecuting Briggs.
During opening statements, Blessington laid out the state's case.
Testimony will include an alleged confession and what Briggs has said to other inmates in jail.
Prosecutors say Dustin's father, Alren Briggs, will also testify that Dustin was the only person outside the home when Deputies Van Kuren and Burget showed up to serve a warrant.
In his opening Statement, Defense Attorney George Lepley says he'll show that the father is not a credible witness.
He says Briggs' girlfriend will testify that Arlen Briggs was also outside the house when the shootings took place.
"As soon as police started talking to him, when they interviewed him, they kept confronting him with inconsistencies in his statement. He kept changing his statement to match what they knew. He'd basically only admit things that he knew they knew for sure," said Defense Attorney George Lepley.
The first witness called to the stand Monday was Pennsylvania State Trooper Edward Urban.
He explained all of the photos taken at the crime scene, pictures that were especially disturbing for the widows of the two deputies.
Testimony will continue Tuesday, starting at 9 a.m.