CASTLE ROCK, Colo. -- Shredded clothing and bits of hair were found along a 1.5-mile-long trail of blood after Luz Maria Franco Fierros was dragged to her death, a sheriff's officer testified Thursday.

Douglas County investigator Mike French described the gruesome aftermath during a preliminary hearing to determine whether Jose Luis Rubi-Nava, 36, should stand trial on charges of first-degree murder and second-degree kidnapping.

She was dragged behind a Saturn sedan, along a paved road, causing horrific injuries to her body.

Prosecutors Thursday for the first time described additional details of the case to a judge who must decide if there's enough evidence to place Jose Luis Rubi-Nava, 36, of Glendale, Colo., on trial for first-degree murder in the slaying, district attorney spokeswoman Kathleen Walsh said.

A judge last fall stopped short of issuing a gag order requested by Rubi-Nava's defense but warned prosecutors and investigators to abide by strict state ethics rules. Those rules limit what attorneys are allowed to say about a case.

Attorneys on both sides have repeatedly declined to comment.

Authorities say the 49-year-old Mexican immigrant was dragged behind a car by her boyfriend until she died by strangulation and massive head wounds Sept 18.

According to prosecutors Fierro's head injuries were extensive: her face was ground away and portions of her skull and brain were visible. Her clothes and breasts were also rubbed away as a result of being dragged on the pavement.

Her body was found along Surrey Drive near the Surrey Ridge subdivision, 20 miles south of Denver.

Investigators found a photograph of the suspect at the scene, and a preliminary autopsy report determined how she died, but few clues have been made public since.

Her death raised more questions than answers for Franco Fierros' friends and family.

Public defender Tamara Brady last year told Douglas County District Judge Paul King the case was garnering undue national attention, referring to a Sept. 21 speech given by Rep. Tom Tancredo, R-Colo., on the floor of the U.S. House when he used the case as an example that the government doesn't do enough to control illegal immigration. The speech was broadcast on the cable network C-SPAN.

Authorities say Rubi-Nava is in this country illegally.

According to the Congressional Record, Tancredo said, "If everybody had done their job there, including the federal government, and the job had been done at the local level, this gentleman would have been off of the streets."

Franco Fierros' neighbor, Zulma Pulgarin, said last fall it seemed like the couple was in love. There were spats, she said, but usually it was Rubi-Nava who was the calmer of the two. Pulgarin said she often had breakfast with Franco Fierros after the two had argued and the fight would be over in a day.

Franco Fierros was a mother of three grown daughters in Mexico and a son who was 17 years old at the time of her death.

Rubi-Nava reportedly had a wife in Mexico.