A Glendale man facing first- degree murder charges for allegedly dragging his girlfriend to death behind his car entered a not guilty plea in court Friday.

Attorneys for Jose Luis Rubi- Nava, 37, told a Douglas County judge their client should be considered mentally retarded, a move that may spare him the death penalty. Tamara Brady said Rubi-Nava has significant "adaptive functioning deficits" and an IQ of 66.

"We're dealing with a first-degree murder case," said Kathleen Walsh, district attorney spokeswoman. "The penalty for a first-degree murder case is life in prison or the death penalty . . .(but)a defendant cannot be legally executed in the state of Colorado if found mentally retarded."

Judge Paul King ruled against defense requests for a hearing to review evidence samples submitted to the Colorado Bureau Investigation for testing, saying that some small samples, including fingernail scrapings, could be "consumed" during the process.

King, however, said defense attorneys could be present during the CBI testing.

Luz Maria Franco Fierros' mangled body was found early Sept. 18 in a Castle Rock subdivision.

Investigators have said Rubi- Nava confessed to killing her after the couple had a violent argument.

Investigators said they found a photograph of Rubi-Nava at the crime scene, which led to his arrest.

Both the suspect and the victim are from Mexico.

Prosecutors have said Rubi- Nava was in the country illegally, and he also faces charges of possessing and using fraudulent government documents.

The judge set a Jan. 8 date for what's expected to be a two- week trial.

craigk@RockyMountainNews.com or 303-954-5618