LONDON (AP) — British police have arrested two men on suspicion of murder after the former Lostprophets singer Ian Watkins was stabbed to death at a prison in northern England, where he was serving a 29-year sentence for child sex offenses.

Emergency services were called to HMP Wakefield in West Yorkshire on Saturday morning after Watkins, 48, was attacked with a knife. He was pronounced dead at the scene.

A murder investigation is underway following the arrests of two men, aged 25 and 43, West Yorkshire Police said in a statement.

In 2013, Watkins pleaded guilty to 13 charges, including trying to rape a baby, sexually touching a 1-year-old, encouraging a fan to abuse her child and making child pornography.

At the time of his sentencing, Judge John Royce called Watkins a manipulative and dangerous sexual predator who had abused his fame to help satisfy his “insatiable lust.”

“Those who have appeared in these courts over many years see a large number of horrific cases,” Royce said in sentencing at Cardiff Crown Court. “This case, however, breaks new ground.''

Watkins was the lead singer for Lostprophets, a Welsh rock band that topped the U.K. charts in 2006 with its third album, “Liberation Transmission." The band announced it was disbanding after Watkins’ arrest.