Updated

An illegal immigrant already serving life in prison for killing a man with a pipe bomb explosion outside a Las Vegas Strip casino in 2007 has been convicted of another bombing several months earlier, court officials said Friday.

A Clark County District Court jury found Porfirio Duarte-Herrera, 31, guilty of attempted murder, bomb making, bomb possession and destruction of property in the Halloween 2006 blast that destroyed a parked pickup truck outside a Home Depot store east of downtown Las Vegas. He could face five to 56 more years in prison.

Senior District Court Judge James Brennan set sentencing June 21.

Duarte-Herrera, of Nicaragua, is already serving life without parole plus 19 to 50 years in the May 2007 bombing that killed a 24-year-old man in the parking lot outside the Luxor hotel-casino. That device was a small pipe bomb with a magnetic switch hidden in a coffee cup and placed atop the victim's car.

Authorities said the Home Depot parking lot bomb was powerful but more rudimentary, and was set off by an electric timing device.

Prosecutor Dave Stanton told The Associated Press the blast whipped shards of metal over a wide area and into a busy nearby street. However, traffic had stopped for a red traffic signal and no one was walking past at the time.

"It was like shooting into a crowd and missing everyone," Stanton said. "It was incredibly lucky no one was injured or killed."

The jury in the Home Depot case heard nothing about the Luxor case until after their verdict on Wednesday. Duarte-Herrera didn't testify during the three-day trial, and Stanton said jurors deliberated about an hour.

Defense lawyers Clark Patrick and Charles Cano said Duarte-Herrera maintains his innocence and they intend to appeal.

Thomas Chittum III, chief agent of the Bureau of Alcohol, Tobacco, Firearms & Explosives office in Las Vegas, said authorities think Duarte-Herrera also detonated a practice bomb in the desert outside Las Vegas some time before the Home Depot blast. Investigators have never found the site.

"It appears that his devices were getting more sophisticated," Chittum said.

The victim in the Luxor case, Willebaldo Dorantes Antonio, was dating the ex-girlfriend of Duarte-Herrera's co-defendant, Omar Rueda-Denvers.

A jury convicted both men of first-degree murder and other charges, but chose to spare them the death penalty. Rueda-Denvers, now 36, is an illegal immigrant from Guatemala who also uses the name Alexander Perez. He is serving life in prison plus 16 to 40 years.