A man from Essex has been found guilty of murdering his 78-year-old step-grandfather.
Brian Hurry died after being hit on the head with a metal bar at his home in Galleywood near Chelmsford last year.
Michael McDonald, who's 25, admitted manslaughter but was found guilty of murder at Chelmsford Crown Court.
The court heard how Mr Hurry died after seeing his mother "have sex with her father in law, Brian".
McDonald said this event led him to lose control and attack Mr Hurry.
McDonald lured him into the bathroom where he hit him numerous times around the head with the metal bar of a dumbbell.
McDonald was on trial alongside his mother Terri Hurry, who was found guilty of perverting the course of justice.
Both are due to be sentenced on Tuesday.