LONDON -- Two bungling British hit men who went to the wrong address and stabbed a schoolboy to death instead of their intended victim have been convicted of murder.

Prosecutors say Ben Hope and Jason Richards were each paid 1,000 pounds (US$1,600) to kill a man who owed money to an underworld figure. But the pair, both heroin addicts, went to the wrong house and killed 17-year-old Aamir Siddiqi on his doorstep.

A jury at Swansea Crown Court unanimously found the pair guilty Friday of the 2010 murder in Cardiff, Wales.

Hope and Richards also were convicted of the attempted murder of Siddiqi's parents, attacked as they tried to save their son.

Judge John Royce said a life sentence is inevitable when the two men are sentenced Feb. 8.