A man was given nearly 25 years more in jail after killing his cellmate (Image: Washington Department of Corrections)

A prisoner who murdered his cellmate after discovering he was in jail for the rape of the man’s sister, has been sentenced to nearly 25 more years in jail.

Shane Goldsby, 26, was seen on video beating Robert Munger, 70, who was serving a 43-year sentence for child rape, child molestation and possession of child pornography, it is reported.

He had reportedly said that he couldn’t believe that he was in the same cell, at the Airways Corrections Center in Washington, as the person who had raped his sister.

Goldsby killed Munger on June 2, last year having been in jail for stealing a police car.

He told the news outlet KHQ in July 2020: “This stuff doesn’t happen. You’re talking the same institution, the same unit, the same pod in the same cell as this dude. That’s like hitting the jackpot in the casino seven times.”

Robert Munger was in prison for the child rape of his cellmate's sister
Robert Munger was in prison for the child rape of his cellmate’s sister ( Image: Kelso Police Department)

An investigation by authorities found that due to differing last names among family members, no link was seen between the two men , according to Spokesman-Review.

The Department of Corrections said it was an “unfortunate and complicated incident,” according to KHQ.

Goldsby said that the situation was coming to a head as Munger was giving him details about “what happened and what he did. About the photos and videos of doing this stuff, it was building up.”

He reportedly said that he asked to be moved into a different cell on many occasions but this never happened and then also no prison guard came when he pressed an emergency cell button ahead of the incident.

Goldby apologised in court to the family Munger for killing him
Goldsby apologised in court to the family Munger for killing him ( Image: Kelso Police Department)

Before Goldsby’s sentencing he apologised to the family of dead man.

His lawyer spoke after the defendant had become overcome with emotion.

The statement read: “I cannot imagine what it would be like to lose a loved on in this kind of way.

“To (Munger’s) wife and his whole family I apologise. I am so sorry and I hope you are able to heal from what I caused.”