Definition: In this task, you will be presented with a passage and have to answer a question based on your understanding of the events inferred from the passage. Try to find the best answer that is most likely to fill in "_". Note that the URLs in the text have been replaced with [Link].
Input: William Beggs (pictured) is known as the Limbs in the Loch killer for raping, murdering and dismembering Barry Wallace, 18, in 1999 A convicted murderer who murdered and dismembered his teenage victim has had boiling hot water thrown over him in an apparent revenge attack in a Scottish prison. William Beggs, 54, known as the Limbs in the Loch murderer, was described by police at the time of his conviction in 2001 as a 'serial killer in the making'. Beggs is serving a life sentence in Saughton Prison, Edinburgh, for raping, murdering and dismembering Barry Wallace, 18, in Kilmarnock, Ayrshire, in 1999.Infamous Limbs in Loch killer William Beggs was attacked in prisonServing life for murdering and dismembering Barry Wallace in 1999Scalded when fellow prisoner threw hot water on him in revenge attack 
 Question:He reportedly told friends he was taking revenge after _ attacked him soon after he arrived at the prison.

William Beggs