British authorities are currently investigating a Sunday prison beating that has been linked to last week’s Woolwich attack that claimed the life of soldier Drummer Rigby.

Three prisoners from Full Sutton prison in East Yorkshire held a warden captive for four hours, threatening him at knife point and brutally beating him with mop handles.

A source inside the prison told the Daily Mirror that “the fear was that the gang had somehow got hold of knives from the prison kitchen and they would attempt to behead him. By the time the attack was finished the officer was covered in bruises and blood. He feels very lucky to be alive. He was told they would kill him.”

The prison’s National Tactical Response Group finally intervened, but not before the warden was dealt serious injuries, including a broken cheekbone. Another female officer sustained minor cuts during the attack. Both have since been released from the hospital.

This assault follows last week’s Woolwich, London attack where two suspected Islamist terrorists, Michael Adebowale and Michael Adebolajo, murdered soldier Drummer Lee Rigby. According to a Telegraph report, the Full Sutton incident occurred after a prison imam told other prisoners to pray for Rigby.

The three responsible for the attack were not being detained for any terror-related activity, although North East Counter Terrorism Unit (NECTU) authorities have determined that they were in fact Muslim. NECTU is further investigating the issue.

“This had all the hallmarks of a pre-planned attack inspired by the Woolwich atrocity,” a source told The Sun. “It’s something officials have been fearing could happen for years, and now it finally has.”

In a 2012 report conducted by the Independent Monitoring Board, officials noted that Full Sutton prison has seen an increase in animosity between Muslim and non-Muslim prisoners. More than one-fifth of those incarcerated in Full Sutton were identified as being Muslim.