DENVER — A Colorado man pleaded guilty to murder charges on Friday for starting a 2020 house fire that killed five members of a Senegalese family out of misplaced revenge for a stolen iPhone that he mistakenly tracked to the house.

Kevin Bui, now 20, was a teenager at the time of the fire but prosecuted as an adult. He has been portrayed by prosecutors as the ringleader of three friends who started the Aug. 5, 2020, fire in the middle of the night in a Denver neighborhood. Bui wrongly…