The leader of a former gang of Houston teenagers who raped and murdered two young girls walking home from a neighborhood party 17 years ago was executed Tuesday in Texas.

Peter Anthony Cantu, 35, was strapped to a gurney in the Huntsville Unit prison death chamber and administered a lethal injection at 6:09 p.m. CDT. He took a single deep breath before slipping into unconsciousness, then was pronounced dead eight minutes later as relatives of his victims, Jennifer Ertman and Elizabeth Pena, looked stoically through a window a few feet from him.

Asked by the warden if he had any last statement, Cantu replied: "No." He never looked at the witnesses, including his victims' parents.

"Nothing he would have said to me would have made any difference," Adolfo Pena, who lost his daughter in the attack, said after watching Cantu die. "He did a horrendous crime to these two girls. He deserved to die and 17 years later, he died. Not soon enough.

"It's been a long time coming," said Pena, who wore a T-shirt bearing pictures of both girls.

Two of Cantu's fellow gang members were put to death earlier, Derrick O'Brien in 2006 and Jose Medellin in 2008. Two other members avoided the death chamber when the U.S. Supreme Court outlawed executing those who were under 18 at the time of their crime. A sixth person convicted in the case was 14 years old at the time of the attack and is serving a 40-year prison term, the maximum sentence for a juvenile in Texas.

Cantu declined to speak with reporters as his execution date neared. In recent years, he stayed clear of trouble and was classified among the best-behaving inmates on death row.

"He has matured remarkably," his appeals lawyer, Robin Norris, said. "He's a guy who fully accepts his responsibility."

"Nobody wants to hear that but it's the absolute truth," trial lawyer Robert Morrow, who remained in touch with Cantu over the years, said.

Trying to make it to Pena's home before an 11:30 p.m. curfew in June 1993, Jennifer, 14, and Elizabeth, 16, took a shortcut after leaving the party that led to a railroad bridge near where the gang members were hanging out drinking and initiating a new member. The group spotted the girls and grabbed Pena, who screamed. Ertman tried to help her friend.

What happened next was "a feeding frenzy," according to Donna Goode, a former Harris County assistant district attorney who was one of Cantu's prosecutors.

The girls were gang raped for more than an hour and forced to perform oral sex. They were kicked, had teeth knocked out and hair pulled out. Their ribs were broken. A red nylon belt was pulled so tightly around Ertman's neck the belt snapped. Shoe laces were used to strangle Pena.

"You're talking about absolute brutality — strangled with hands, strangled with ligatures, belts, shoestrings," Don Smyth, Goode's prosecution partner, recalled. "And just to be sure, they were stomped on their faces and their throats were crushed.

Goode said the evidence showed Cantu was the ringleader, "kind of the alpha male of the group."

Morrow said the victims were "so sympathetic and rightly so. I don't think anybody on our side would disagree with that."

A tip led authorities to the bodies. A day later, Cantu's brother, upset after hearing the teens gloat about having fun with the girls, provided the tip to police that led to the arrests of the six.

Cantu was the first of five to be tried, convicted and sentenced to die.

Speaking from the death chamber four years ago, O'Brien, 31, called his involvement in the murders "the worst mistake that I ever made in my whole life."

Medellin, 33, who was born in Mexico, similarly apologized before he was put to death.

Jennifer's father, Randy Ertman, who witnessed all three executions, said before Cantu was put to death Tuesday that the apologies meant nothing to him, that it was too late for apologies.

"It don't bother me a bit," he said of witnessing. "It's crazy. But you've got to be mentally prepared ... to get through it. Whatever you throw at me, I can take it. I have to think that way. It's hard but I can take it."

Ertman said if the death penalty was intended as a deterrent, all five members who had been sentenced to die should have been hanged from trees outside Houston City Hall years ago.

"That would be a deterrent," he said.

All of Cantu's appeals had been exhausted and the Texas Board of Pardons and Paroles rejected a plea to commute his sentence to life in prison.

Cantu's execution was the 16th this year in Texas, the nation's busiest death penalty state.