The state is expected to rest its case against teen murder suspect Bradley Renfro when the trial resumes Monday. 

Thursday marked the twelfth day of Renfro's murder trial. He's one of four teens accused of pistol-whipping, kidnapping and killing 16-year-old David Grunwald in November 2016.  

Palmer District Attorney Roman Kalytiak wrapped up testimony with his last witness Thursday morning: Alaska State Trooper Sgt. Tony Wegrzyn, who is the lead investigator on the Grunwald murder case.

Wegrzyn told the the jury he cannot say with confidence who shot Grunwald and explained why none of the defendants could be trusted to testify against each other. 

"In my opinion it's the continued deception amongst all the parties prohibits our ability to truly know who pressed the trigger that night and despite numerous efforts to try to get them to be a good witness or be a witness at all, we can’t definitively say they didn’t pull the trigger nor can we say that they did," he said.

Renfro’s defense attorney Chris Provost began his cross examination of Wegrzyn. He questioned the trooper about a phone number in call records from Dominic Johnson's phone the night Grunwald was killed and why investigators did not interview the person on the other end of two calls lasting three and five seconds. 

Provost noted his client's age, weight and height at the time of the murder and showed jurors a photo of the group in court depicting Renfro as the smallest one. He asked Renfro to stand, noting he has grown since the nearly 3-year-old crime.

He introduced a photo of Sarah Palin holding up two fingers and smiling — noting that the former governor of Alaska was inadvertently holding up what is known to some as a gang sign. 

AST Sgt. Wegrzyn holds a photo Renfro's defense attorney says shows former Alaska Governor Sarah Palin inadvertently making a gang sign with her hands. (Daniella Rivera / KTVA)

Then he began to delve into the interviews between Renfro and troopers. He said Renfro’s mother mentioned before one of the interviews that she couldn't afford an attorney.

During the interview, Renfro told his mother he didn't need one. 

"Do you think he understood what lawyers did at that point in his life," Provost asked.

"You’re asking me what I thought he understood? I have no idea," Wegrzyn answered. "I mean, at 16, I think I knew what a lawyer did at 16."

"I didn't," Provost countered. 

"Well maybe we could put him up here and ask him," Wegrzyn replied.  

Provost said, "I have." 

The cross examination is expected to continue Monday. It is unclear whether Renfro will take the witness stand in his own defense. 

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