A Mexican drifter who became known as the "railroad killer" has been put to death by lethal injection in Texas.
Lawyers said Resendiz believed he was half-man, half-angel
Angel Maturino Resendiz, 46, was sentenced to die for the rape and murder of Dr Claudia Benton in 1998, but was linked to 14 other killings.
Resendiz travelled by train and many of the murders took place near railway tracks, earning him his nickname.
His lawyers and the local Mexican consul had asked the Supreme Court to stay the execution, but it refused.
His lawyers had argued he was delusional, believing himself to be half human and half angel, but courts ruled him mentally competent to face the death penalty.
Resendiz asked the relatives of his victims to forgive him in his last moments, adding: "You don't have to. I know I allowed the devil to rule my life."
He murdered Dr Benton, 39, in her home in Houston in December 1998.
He entered the house while Dr Benton slept and raped, stabbed and bludgeoned her in a killing homicide detectives described as particularly brutal.
Dr Benton's husband George attended the execution and said Resendiz was "evil contained in human form, a creature without a soul, no conscience, no sense of remorse, no regard for the sanctity of human life", the Associated Press reported.
Resendiz either confessed or was linked by evidence to the killings of 13 other people over a 16-month period ending in June 1999, as well as a murder in San Antonio in 1986.
The double killing of Pastor Norman "Skip" Sirnic and his wife Karen in Weimar, Texas, elicited particular revulsion from the public. They were battered to death with a sledgehammer.
Weeks later, the body of 73-year-old Josephine Konvicka was found at her home on the town's outskirts.
Resendiz - who was on the FBI's 10 Most Wanted list - was, at one point, detained by US immigration authorities, but was deported to Mexico without questioning because of a computer error.
He surrendered to the police in July 1999 after his sister Manuela persuaded him to give himself up.
She was reportedly afraid he would kill more people - possibly including her.
Resendiz's lawyers argued that he was a schizophrenic who was convinced he would not die but would return three days after his execution.
But at the end of a three-day hearing last week, state district judge William Harmon said there was "no doubt in my mind" Resendiz understood his situation and the sentence he faced.
Defence lawyers' appeals were rejected by a federal judge in Houston and the Texas Board of Pardons and Paroles on Monday.
The Supreme Court rejected fresh appeals on Tuesday from his lawyers and from the Mexican consul in Houston. Mexico's foreign ministry also protested against the sentence.
The legal wrangling delayed the execution by about two hours.
He was the 13th person to be executed in Texas this year.