CASTLE ROCK, Colo. — A man was arrested in the gruesome dragging death of a woman after a stained and tattered photograph of him was found at the crime scene, police said yesterday.

Jose Luis Rubi-Nava, 36, was arrested Tuesday night on suspicion of murder and jailed without bail. Investigators said they were still trying to identify the victim, who was dragged behind a vehicle with a rope, leaving a trail of blood more than a mile long.

Authorities did not immediately respond to questions about how the photograph ended up near the woman’s body, which was discovered Monday in a suburban neighborhood about 20 miles south of Denver.

The photo had been released to the public, and Sheriff Dave Weaver said tips from citizens helped lead to the arrest, but he did not elaborate.

Mr. Weaver offered no motive for the killing.

The picture shows a couple who appear to be in their 30s, with the man leaning his arm on the woman’s shoulder. Investigators did not say whether the woman in the picture was the victim.

An Immigration and Customs Enforcement spokesman, Carl Rusnok, said agents believe Mr. Rubi-Nava is an illegal immigrant from Mexico.

Neighbors discovered the woman’s body before dawn. Her face was unrecognizable, and an orange tow-rope was around her neck, Nancy Foley, who lives near where the body was found, said.

An autopsy indicated the woman died of asphyxiation and head injuries from being dragged.

The trail of blood led from Interstate 25 to the woman’s body, which was found on a street lined with large ranch-style homes on spacious lots. Yesterday, highway crews were spreading fresh tar over the roads to cover the traces of blood.