CHANDLER, AZ (3TV/CBS5) -- Chandler police arrested a man accused of raping two women more than two decades ago.
The sexual assault cases went cold after detectives couldn't identify a suspect.
New today, Chandler police announced there has been a huge break in in the cases.
Detective Seth Tyler identified the suspect as an undocumented immigrant who was already in federal custody, serving his sentence after being convicted of crossing into the U.S. illegally.
In September 1997, a 22-year-old woman was sexually assaulted by an unknown man at Hoopes Park, near Alma School and Elliot roads.
Ten days later, an 18-year-old girl was sexually assaulted by a man inside her home near Arizona Avenue and Ray Road.
Chandler police believed the same man raped both women. Detectives collected physical evidence from both crime scenes, including DNA.
They were not able to identify a suspect and the cases went cold.
"This evidence essentially sat for almost four years until the technology developed to where we could send it off for it to be entered into the database and then for it to be analyzed," said Tyler.
It took years to find a match.
"When Lopez-Perez was placed into federal custody, law required that he submit to a DNA sample and that's how we were able to get that DNA sample," he explained.
In April 2019, DNA from both cases matched to 43-year-old Adan Lopez-Perez, a Mexican national who lived in Chandler in 1997, was in custody for unlawful entry into the United States.
However, it almost didn't happen.
"My understanding is he had been incarcerated for a couple months. I was told when our department was notified, he was four days away from being released," said Tyler.
"Our detectives actually worked around the clock," he added. "The time, the clock....it's ticking, because there's a time where this individual could be released and we'd have to start the process all over again."
[CBS 5 INVESTIGATES: DNA profiles helping police catch serial rapists]
On April 8, Lopez-Perez was arrested for his involvement in both sexual assaults. He was booked into Maricopa County Jail on five counts of sexual assault, two counts of sexual abuse, three counts of aggravated assault, two counts of kidnapping and one count of burglary.
Immigration and Customs Enforcement spokeswoman Yasmeen Pitts O'Keefe released the following statement to Arizona's Family Friday morning.
“Adan Lopez-Perez, a Mexican national and nine-time previously removed criminal alien, was recently encountered by Deportation Officers with ICE’s Enforcement and Removal Operations (ERO) at the Maricopa County Jail April 9, 2019, after his arrest on multiple counts of sexual assault and kidnapping. ERO officers lodged an ICE detainer with the Maricopa County Sheriff’s office on the Lopez-Perez case.
Relevant checks reveal that Lopez-Perez was sentenced for a felony re-entry conviction as recently as April 3, 2019.”