HOLLIDAYSBURG — A 19-year-old Altoona man accused of beating a fellow Blair County Prison inmate almost a year ago was found guilty Wednesday of simple assault and disorderly conduct.

The jury took about 20 minutes to render verdicts convicting Matthew R. Sander­lin, who was accused of beating a fellow inmate believed to be a snitch.

“(The whole cellblock) knew I knew something, and I was probably going to tell,” the victim inmate told the jury in explaining what led up to the March 21, 2017, assault in his jail cell.

“I walked into my cell, and (Sanderlin) was standing there with his shirt off, ready to go,” the victim testified. “I threw a punch, he threw a punch … and I woke up on the ground. … I blacked out.”

The victim suffered a black eye and needed stitches to close an area where one of his teeth went through his lip. In prison video played for the jury, the victim’s cellmate is seen carrying a mop into the cell, allegedly to clean up blood. Sanderlin, who also testified, tried to convince the jury that he should be cleared of the charges because he didn’t start the fight. Sanderlin admitted to being in the victim inmate’s cell. He said he was smoking a cigarette when the victim came in and threw the first punch. Sanderlin also said he had gone into that cell to return a battery for a cigarette lighter.

“He’s a liar,” District Attorney Richard Consiglio told the jury in his closing statement, referring to Sanderlin.

Consiglio and Assistant District Attorney Amanda Jacobson provided the jury with video recorded at the prison of inmate activity in the E block dayroom, an area accessible to all inmates when they’re out of their cells.

Because of that video, the jury could see Sanderlin and the inmate victim go in and out of the jail cell where the assault occurred. No video of the fight was shown because there are no cameras in the cells.

Assistant Public Defender Anthony Kattouf tried to convince the jury that his client should be cleared.

“I think he truly believes that he wasn’t guilty because he didn’t start the fight,” Kattouf said after the trial.

But Sanderlin was responsible, Consiglio said, because the fight was a way of trying to keep the victim from disclosing what he knew about an earlier incident at the prison.

“I have no doubt that’s why the (victim) was attacked,” Consiglio said. “It took a lot of courage for him to do the right thing by coming forward with what he knew, and he paid a price for it.”

Jurors were not advised about the specifics of the earlier incident, but it involved the alleged sexual assault of an inmate on E block that occurred five days earlier and led to criminal charges.

Judge Daniel Milliron, who presided over the trial, scheduled Sanderlin’s sentencing for April 20 and ordered the county parole and probation department to conduct a presentence investigation.

Sanderlin is currently incarcerated at the State Correctional Institution at Pine Grove, Indiana, serving a three- to six-year sentence on two counts of aggravated assault.

Those charges developed from a fight in Altoona in September 2016 when he was 18 years old and used a knife to injure two 17-year-old youths.

Mirror Staff Writer Kay Stephens is at 946-7456.