This is from the oldest extant biography of Muhammad called the "Sirat Rasulallah" — "Life of the Prophet of Allah".
Muhammad aggressively attacked several groups of people around him. One of these groups were the Jews of Khaibar. Muhammad believed God led him to attack Khaibar. After Khaibar was conquered, the Jews were either enslaved, executed, or allowed to live there provided they gave the Muslims one half of all they produced. This probably being the first historical recoding of the protection racket.
One of the 'Prophet's' most brutal acts involved a prisoner named Kinana, one of the leaders of Khaibar. Muhammad wanted him to reveal where some buried treasure was hidden. Kinana refused. Muhammad had him tortured to the point of death. "Torture him until you extract what he has." So he kindled a fire with flint and steel on his chest until he was nearly dead.
When that didn’t work out the ‘Prophet’ had him beheaded.
Such are the origins of the ‘Prophet’ and the ‘Religion of Peace’