A prisoner at SCI Phoenix was killed by another inmate, police say. It was the second such killing this year.

An inmate at the state Correctional Institution at Phoenix was killed inside the prison last week, and his death is being investigated as a homicide, state officials said Monday.

Shaun Harden, 45, was found unresponsive in his cell Friday evening, according to the state Department of Corrections. Staff at the prison attempted to revive him, but he was pronounced dead at 6:29 a.m. Saturday.

Harden, of Nemacolin, Greene County, was serving a four-to-eight year sentence in state prison after being convicted in 2015 of indecent aggravated assault of a child, corruption of minors, and related crimes. According to an article in the Washington County Observer-Reporter, Harden fondled an 11-year-old girl and two boys, 11 and 12, in separate incidents between June and October 2014.

A spokesperson for the Pennsylvania State Police confirmed Monday that Harden’s death is being considered a homicide, and that the Montgomery County District Attorney’s Office is handling the investigation. No charges had been filed as of Monday evening.

How Harden died remained unclear. Sources at the prison familiar with the investigation who asked not to be identified because they were not authorized to discuss it said Harden had recently been put into a cell with another inmate, and that the man fatally attacked him.

Harden’s death marks the second time this year that an inmate at SCI Phoenix was killed inside the prison. In August, Dwight Williams stomped Ashokkumar Guru to death inside his cell, according to prosecutors.

Williams, 42, was charged with first- and third-degree murder, and is awaiting a criminal trial in Montgomery County.