A judge ruled Wednesday that serial killer Angel Maturino Resendiz, who gained notoriety as the "Railroad Killer" linked to at least 15 murders across the country, is mentally competent to be executed next week for the 1998 rape-slaying of a Texas doctor.

Resendiz' attorneys had argued that the 46-year-old Mexican national is delusional and believes he is half-man, half-angel and will return three days after going to the death chamber.

"He knows he's been convicted of capital murder," State District Judge William Harmon said Wednesday at the conclusion of a three-day hearing. "He knows he's received a death sentence and he knows that today. And he knows he's going to be executed on Tuesday."

Resendiz was convicted of killing Claudia Benton, a researcher at the Texas Medical Center, who was stabbed, beaten with a statue and raped in her Houston home.

Overall, he has been linked to eight slayings in Texas, two in Illinois, two in Florida, and one each in Kentucky, California and Georgia between 1986 through June 1999. Most were near railroad tracks, drawing the nickname "Railroad Killer." Four occurred after the Border Patrol nabbed him as an illegal immigrant and returned him to Mexico, not realizing he was on the FBI's Most Wanted list.

Resendiz's lawyer, Jack Zimmerman, said he would appeal Wednesday's decision.

"I think the judge gave us a fair hearing," Zimmerman said. "Obviously, we think he reached the wrong conclusion."

At another hearing this week, psychiatrists testifying for the defense said Resendiz is schizophrenic and delusional, fears government conspiracies and believes he will survive his lethal injection. They said he told them he would awaken three days after his execution and be in the Middle East to help Jews fight Arabs.

Prosecution psychiatrists, however, said after examining Resendiz in jail over the past several weeks that while he may have delusions, he's not schizophrenic and should be eligible to be put to death.

Resendiz sat at the defense table in handcuffs Wednesday and appeared to pay close attention during the hearing, occasionally chatting with his attorney. Since he has a history of self-mutilation, he is not allowed to have sharp objects such as razors, and he has grown a long beard.

Zimmerman, whose firm was hired by the Mexican government to represent Resendiz, said his client's guilt and punishment weren't at issue, but he said the law mandates that people to be executed must understand they are going to die.

Roe Wilson, a Harris County assistant district attorney, said Harmon's ruling addressed the basics of the legal test for execution.

"It's not: Are you paranoid schizophrenic, are you delusional?" the prosecutor said. "It's: Are you aware you're going to be executed, and that it's imminent and the reason for it? And Resendiz showed that over and over and over by what he told all of the doctors."

"Resendiz is eminently competent to be executed. This was a final maneuver in his yearslong manipulation of the system," Wilson said.

If the execution takes place Tuesday, Resendiz, dubbed "Choo-Choo Man" by other death row inmates, would become the 13th inmate executed this year in Texas.