The Chandler Police Department said in a statement cited by AZ Central that a DNA sample taken around the time of the crime was successfully matched decades later in April 2019 with DNA recently collected from 43-year-old Adan Lopez-Perez.
Lopez-Perez was required to submit a DNA sample as part of an investigation into his alleged illegal entry into the United States. He was in federal custody when the sample was collected.
According to AZFamily, Lopez-Perez was arrested on April 8 for his alleged involvement in the crimes.
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.
Police said Lopez-Perez lived in Chandler when the sexual assaults took place.
In one incident, a male suspect sexually assaulted a 22-year-old woman in September 1997 in a local park. Ten days later, a male suspect sexually assaulted an 18-year-old woman inside her Chandler home, according to 12News.
Detectives collected DNA samples at both crime scenes, but it took five years for the two assaults to be linked to the same suspect.
But well over a decade would pass until Lopez-Perez—a Mexican national said by investigators to be in the United States illegally—would be connected to the crimes.
Detective Seth Tyler was cited by Arizona’s Family as saying that Lopez-Perez had nearly been released by the time detectives identified him as the suspect in the decades-old assaults.
“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,” Tyler told the publication.
“Our detectives actually worked around the clock,” he said. “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.”
According to AZ Central, citing court documents, Lopez-Perez was extradited to Maricopa County after he was released from federal prison.
Court paperwork cited in the report indicates a grand jury warrant asked for a $250,000 cash bond and electronic monitoring for the suspect.
Crime in the United States
Violent crime in the United States has fallen sharply over the past 25 years, according to both the FBI’s Uniform Crime Reports (UCR) and the Bureau of Justice Statistics (BJS) National Crime Victimization Survey (NCVS).
The rate of violent crimes fell by 49 percent between 1993 and 2017, according to the FBI’s UCR, which only reflects crimes reported to the police.
The violent crime rate dropped by 74 percent between 1993 and 2017, according to BJS’s CVS, which takes into account both crimes that have been reported to the police and those that have not.
“From 1993 to 2017, the rate of violent victimization declined 74 percent, from 79.8 to 20.6 victimizations per 1,000 persons age 12 or older,” the U.S. Department of Justice stated (pdf).
Both studies are based on data up to and including 2017, the most recent year for which complete figures are available.
The FBI recently released preliminary data for 2018. According to the Preliminary Semiannual Uniform Crime Report, from January to June 2018, violent crime rates in the United States dropped by 4.3 percent compared to the same six-month period in 2017.
While the overall rate of violent crime has seen a steady downward drop since its peak in the 1990s, there have been several upticks that bucked the trend.
Between 2014 and 2016, the murder rate increased by more than 20 percent, to 5.4 per 100,000 residents, from 4.4, according to an analysis of FBI data. The last two-year period that the rate soared so quickly was between 1966 and 1968.
The property crime rate fell by 50 percent between 1993 and 2017, according to the FBI, and by 69 percent according to BJS.
According to the FBI’s preliminary figures for the first half of 2018, property crime rates in the United States dropped by 7.2 percent compared to the same six-month period in 2017.
As with violent crime, the FBI survey only takes into account crime reported to the police, while the BJS figures include reported and nonreported crime.
Public Perception About Crime
Despite falling long-term trends in both violent crime and property crime, opinion surveys repeatedly show Americans believe that crime is up.
The vast majority of Gallup polls taken since 1993 show (pdf) that over 60 percent of Americans believe there is more crime in the United States on a national scale compared to the previous year.
Pew Research surveys show similar findings. A survey in late 2016 revealed that 57 percent of registered voters said crime in the nation as a whole increased since 2008, despite both FBI and BJS data showing double-digit drops in violent and property crimes.
Perceptions differed on a national versus local level.
Surveys of perceptions of crime levels on a local scale showed that fewer than 50 percent of respondents in every single Gallup survey (pdf) done since 1996 believed that crime in their area had risen compared to the previous year.