BOULDER, Colo. - A DNA sample from a man now facing first-degree murder charges in a 10-year-old case sat in Wyoming's crime lab for about seven years because of appeals and a backlog of thousands of cases.

Diego Olmos-Alcalde, 38, sat handcuffed and shackled in court as prosecutors filed murder charges Wednesday in the 1997 death of 23-year-old Susannah Chase, a University of Colorado student. He faces two counts of first-degree murder, sexual assault and kidnapping.

The 5-foot-8, 150-pound Olmos-Alcalde was dressed in a prison uniform with wide orange and white stripes and answered, "Yes, sir," as Judge James C. Klein asked him if he understood his rights. He waived his right to a preliminary hearing within 30 days.

The two-day hearing has been scheduled starting April 23. Olmos-Alcalde is being held on $5 million bail.

One count of murder was based on deliberation, and another count was based on murder during the commission of a felony, said Boulder County DA spokeswoman Carolyn French.

Chase, of Stamford, Conn., was beaten with a baseball bat, sexually assaulted and left unconscious in an alley on Dec. 21, 1997. She died at a hospital the next day. Police questioned her boyfriend and friends shortly after the slaying, ruling them out as suspects based on semen found on Chase.

The case went cold until Jan. 24, when the Wyoming Crime Laboratory found a match from Olmos-Alcalde, who had submitted a sample in 2001 following a felony kidnapping conviction.

Olmos-Alcalde, who was living in Aurora when arrested Jan. 26, repeatedly denied any knowledge of Chase's death and said he had not been in Boulder since he was 16 years old.

Despite submitting his sample in 2001, Wyoming officials removed it from a national database when he appealed his conviction. He was retried and convicted in 2004, but his DNA wasn't re-entered until mid-January.

Wyoming Crime Lab Director Steve Holloway said there's a backlog of some 10,000 samples waiting to be loaded into the database, in addition to 1,500 new samples per year.

"We have an aggressive program right now and hope to have that backlog cleared by the end of this year," Holloway said.

Police also had contact with Olmos-Alcalde in the weeks after the slaying. On Jan. 1, 1998, they arrested him after a woman said she was raped and held at knifepoint, according to an arrest affidavit.

Denver DA spokeswoman Lynn Kimbrough said no charges were filed because of "no reasonable likelihood of conviction."

Olmos-Alcalde was arrested again on Jan. 16, 1998, after a woman said a man held a knife to her throat after he offered her a ride. The woman jumped out of the car and alerted a nearby police officer who arrested Olmos-Alcalde, the affidavit said. Olmos-Alcalde pleaded guilty to carrying a concealed weapon and prosecutors dropped a charge of attempted sexual assault, Kimbrough said Wednesday.

She said the victim supported the plea agreement because she did not want to go through the trauma of testifying at trial.

Olmos-Alcalde was sentenced to time served in jail and released six months after his arrest in that case.

Olmos-Alcalde was released in Wyoming last year. He was turned over to Immigration and Customs Enforcement officials, who determined the Chilean native was in the country legally and did not meet the requirements for deportation.

As part of his parole, he was to report to Wyoming officials upon his release from ICE custody but did not. An arrest warrant was issued in October.

Wyoming Parole Board Executive Director Patrick Anderson said paroled inmates sent to ICE are there because they expect they will be deported. He said they're working on establishing a mechanism where such inmates would be sent back to Wyoming custody if they're not deported.