DENVER (AP) -- Lawyers for a man convicted of the 1993 ambush slayings of four people say he had undiagnosed bipolar disorder at the time and shouldn't be executed.
Nathan Dunlap's attorneys formally asked Gov. John Hickenlooper for clemency on Monday.
Dunlap faces execution as early as August for the shooting deaths at a Chuck E. Cheese restaurant in suburban Denver.
He was convicted and sentenced to be executed in 1996, and the U.S. Supreme Court turned down his last guaranteed appeal in February. This month, a judge scheduled Dunlap's execution for the week of Aug. 18, with the day to be set by prison officials.
Hickenlooper hasn't said how he would respond to a request for clemency. He met Friday and Saturday with victims' family members and others to hear their views.