MEXICO CITY -- Mexican authorities searched Friday for a third man wanted for questioning in connection with the rape and slaying of four teenage girls in Texas last year.
The search for Ricardo Hernandez continued following the arrest by Mexican police Thursday of two men officials claim confessed to killing the four teenagers on Dec. 6, 1991, at a north Austin yogurt shop.
The Mexican attorney general's office said Porfirio Villa Saavedra, 28, and Alberto Jimenez Cortez, 26, admitted they killed Amy Ayers, Eliza Thomas and sisters Jennifer and Sarah Harbison.
However, the two men are awaiting indictment on charges they raped and kidnapped a 23-year-old Texas woman one month earlier and are merely suspects in the death of the four girls.
An office spokesman said the indictment could take place over the weekend.
Hernandez, whose wherabouts remained unknown Friday, is also wanted for questioning in the rape and kidnapping.
The two men in custody are Mexican nationals, and cannot, under Mexican law, be extradited to the United States. Instead, they will face trial and any subsequent jail time in Mexico.
The nation does not have a death penalty, but authorities said the men face up to 50 years in prison if convicted of homicide. Additionally, Villa and Jimenez face separate narcotics charges for crimes allegedly committed in Mexico, and are under suspicion of gun- running.
Despite Villa and Jimenez's alleged admissions of guilt, observers often view Mexican crime confessions with skepticism, because of widespread charges of police coercion.
Nonetheless, Mexican authorities said all three men appear to be members of a notorious motorcycle gang believed responsible for a string of crimes in both Austin and Mexico.
Austin police, who also appeared at Thursday's news conference to announce the arrests, said they had been instructed not to comment on case.
Austin Senior Sgt. Hector Riveles declined to say whether he thought the Mexican police had the right men, but praised cooperation between the two nations in locating the suspects.
A Travis County, Texas, grand jury indicted the three suspects earlier this year in the kidnapping and rape of a woman abducted from an Austin nightclub.
Police later noticed one of the men fit a discription of a suspect seen outside the north Austin I Can't Believe It's Yogurt! shop the night of the killings. By that time, the suspects had already fled to Mexico.
Austin homicide investigator Lt. David Parkinson traveled to Mexico City last month to get Mexican authorities involved in the search.
Mexican police picked up Villa Saavedra, 28, early Thursday in Puerto Vallarta, a resort town on Mexico's western Coast. Authorities seized Jimenez Cortez on the outskirts of Mexico City.
Police said the four Austin girls, ranging in age from 14 to 17, were killed with gunshots to the head before the assailants set the shop on fire in an apparent attempt to destroy evidence.
The crime stunned Austin residents, who held candlelight vigils for the girls and launched an intensive campaign to find their killers.
The effort included a billboard campaign that featured photos of the four victims, along with the caption, 'Who Killed These Girls?' Reward offers eventually reached $100,000, and police set up a special task force to handle the case.
The CBS News program '48 Hours' also profiled the killings in an episode that became the series' second-highest rated program to date.
Thursday, Pam Ayers, the mother of victim Amy Ayers, said she had mixed emotions about the arrests.
'It would be nice if it could be them, so we could bring this to some type of an ending -- as far as the drudgery of every day waking up and wondering, 'Will today be the day we find out who killed our girls?'' she said. 'But it's mixed emotions. It's a day you want to come, but a day you dread at the same time.'