SAN ANTONIO -- The so-called "Railroad Killer" has confessed to three unsolved murders in San Antonio, KSAT 12 News reported Tuesday in an exclusive report.

Angel Resendiz (pictured, left), who is sitting on Texas' death row for the murder of a Houston doctor, claimed to have committed the murders in the mid-1980's, San Antonio police and Bexar County sheriff's department officials said.

Resendiz told authorities that when he lived at the Samm Shelter, he murdered a Cuban man and then dumped the victim's chopped-up body in a creek along Highway 90.

But SAPD homicide detectives said Resendiz' story didn't pan out, and neither did a second crime the self-proclaimed serial killer confessed to.

Resendiz' claim to a third murder, though, did crack a murder mystery wide open.

Bexar County Sheriff's Department Sgt. Sal Marin told KSAT 12 News police beat reporter Gina Galaviz that one of the serial killer's confessions matched an unsolved murder.

In 1986, authorities found the body of a woman on Weichold Road and Loop 1604. The unidentified victim was shot several times, Marin said.

"Sooner or later ... serial killers are linked to these type of murders," Marin said.

SAPD officials and other law enforcement agencies said they plan to look closer at their cold cases to see if Resendiz can help them solve the murder mysteries.