DENVER -- Authorities say a man arrested in Colorado is suspected of raping 11 women in New Mexico and Texas over a 15-year span and, more recently, trying to kill a Colorado police officer.

Police in Albuquerque and Pueblo, Colo., are checking to see if 47-year-old Robert Howard Bruce, of Pueblo, might have been involved in other unsolved crimes.

Albuquerque Police Department spokesman John Walsh said Bruce was tied to the Albuquerque rapes -- which go back as far as 1991 -- after his DNA matched one case.

Walsh said police think Bruce may have committed crimes from 1991 to 2000 in Albuquerque and a 2006 rape near the University of Texas in Austin.

All of the Albuquerque rapes occurred near the University of New Mexico. Authorities there called him the "Ether Man" because all of his victims were rendered helpless by chemical-laced cloths placed over their mouths. The Texas victim was also raped in the same way.

In most of the "Ether Man" cases, the rapist broke into victims' homes, rendered the victims unconscious and then raped the women. Despite the name "Ether Man," Walsh said the chemical that the rag was soaked in was not ether.

Bruce lived in Albuquerque, Rio Rancho and Raton, N.M., from 1988 to 2003, Walsh said.

Albuquerque authorities have issued a warrant for Bruce's arrest. There is a $3 million bond attached to the warrant.

"This is a perfect example that we never give up, we are the ones that speak for those victims, literally and to coin a pun, the long arm of the law reached backed 18 years and is holding this man accountable," Walsh said.

The Pueblo County Sheriff's Department in Colorado arrested Bruce on Oct. 6 after a police officer found a 30-pound propane tank rigged to pump gas through his attached garage. Bruce was later arrested and faces three counts of attempted first-degree murder, intimidation of a witness, possession of an incendiary device and third-degree criminal trespassing.

The Pueblo officer was supposed to testify that day in a trial involving Bruce, who was charged with unlawful sexual contact -- peeping Tom and second-degree trespassing.

Authorities said Bruce didn't show up for the trial that day.

Detective Rich Lewis from Albuquerque's Cold Case Unit connected the original Peeping Tom case in Pueblo with the "Ether Man" rape cases in New Mexico. Comparison of DNA indicated that Bruce is the "Ether Man," who has been sought for nearly two decades, Pueblo police said.

DNA evidence in CODIS also indicates that he may have been involved in another rape case in Austin, Texas.

There are many victims of the "Ether Man" and at least one more came forward after his arrest, Walsh said.

Police believe there are more victims who have not come forward.

"We would encourage anyone who may have been a victim of the 'Ether Man' to come forward now," said Pueblo County Sheriff's Deputy Laurie Kilpatrick.

Please contact the Pueblo County Sheriff's Office at (719)583-6250, the Pueblo Police Department at (719)553-2502 or the Pueblo District Attorney's Office at (719)583-6030.

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