The man convicted of killing four people at a pizza restaurant in 1993 lost another round in his battle to avoid execution on Monday when the Colorado Supreme Court rejected his claim that his legal defense was ineffective.
The justices ordered that the trial court set a date for Nathan J. Dunlap's execution.
Dunlap's attorney, Philip Cherner, said he would ask the court to reconsider. If that fails, Cherner said, he will launch an appeal through the federal courts.
"We believe our appeal has merit and we will eventually prevail," he said.
Dunlap, 33, was convicted in 1996 of shooting five people at a Chuck E Cheese restaurant in suburban Aurora when he was 19. Four of the victims died.
The state Supreme Court upheld his death sentence in 2001. In 2004, Dunlap began another appeal, claiming his representation was inadequate. The court rejected that claim Monday.
"We dissolve the stay of execution and remand this case back to the trial court to set a date for imposition of the death sentence," the justices said in their ruling.
Dunlap was convicted of first-degree murder, attempted murder, robbery, theft and burglary for the Chuck E Cheese shootings on Dec. 14, 1993.
Employees Sylvia Crowell, 19; Benjamin Grant, 17; Margaret Kohlberg, 50; and Colleen O'Connor, 17, were shot to death.
Bobby Stephens survived and later identified Dunlap as the murderer.
Dunlap was a former employee of the restaurant.
Crowell's father, Bob Crowell, said he feels their family is one step closer to justice after Monday's ruling.
"It left a big hole in our family, of course," he said. "And 13 1/2 years is way longer than the process should take. Slow justice is no justice."
Bob Crowell said he and his family are just want this part to be over.
"Don't get me wrong. I am not a violent type guy," he said. "I just think the public deserves justice."
Associated Press contributed to this story.