A 35-year-old Chandler man is facing a felony charge after police say a recorded phone call captured him admitting to sexually assaulting a 16-year-old girl at an apartment complex swimming pool near Price and Germann roads. Robert Mark Vicente Casillas was taken into custody Thursday morning, and investigators say surveillance footage and his own recorded words during the call helped seal the case against him.
According to FOX 10 Phoenix, the alleged assault happened on July 1 while the teenager was sunbathing on a float at the pool. Casillas approached her on the float, grabbed her in what police described as a bear hug, and pulled her into a deeper section of the pool. He also offered to apply sunscreen to her back, according to the outlet's account of court records.
Court records state the teenager told Casillas she was 16 years old before the alleged assault, a detail that matters under Arizona law. Sexual conduct with a minor between the ages of 15 and 17 is classified as a Class 6 felony when there is no position-of-trust relationship between the accused and the victim, according to Arizona Revised Statutes covered by FindLaw. The same statute eliminates mistake of age as a defense, meaning prosecutors would not need to prove Casillas knew the teen's exact age even without that alleged disclosure, per an explanation from Stone Rose Law.
How the Recorded Call Became Central Evidence
The teenager and her family had returned from a trip out of town for a relative's funeral before detectives arranged to monitor a phone call between her and Casillas on August 18, the report notes. During that recorded conversation, per police, Casillas made incriminating admissions about touching the teenager and apologized to her.
Chandler detectives were legally able to monitor the call without a wiretap warrant because Arizona is a one-party consent state, meaning law enforcement can record a phone conversation as long as one participant — in this case, the teenage victim — agrees to it, according to a legal explainer from the Digital Media Law Project. Pretext calls like this one are a standard investigative tool in Arizona sex crime cases. When Chandler police later interviewed Casillas following his arrest, court records indicate he initially denied touching the teenager before admitting the assault happened, per those same records.
Investigators also obtained apartment pool surveillance footage that confirmed the victim and Casillas were together in the pool during the timeframe described in the case, and court documents state Casillas sexually assaulted the victim. Casillas was booked into Maricopa County jail and charged with felony sexual conduct with a minor. He is being held on a $250,000 bond and is scheduled for his next court date on August 27.
A Criminal Record That Could Shape Sentencing
Casillas has an extensive criminal record in Arizona, including prior convictions for drug offenses, weapon violations, and criminal damage, as well as a previous arrest for smuggling illegal migrants, the station's report states. That history could carry significant weight if he is convicted on the current charge. Under Arizona Revised Statutes covered by the Salwin Law Group, a defendant convicted of a Class 6 felony with two or more historical felony convictions faces a mandatory prison term of 2.25 to 5.75 years and becomes ineligible for probation — a stark contrast to the probation eligibility available to first-time offenders under the same statute.
His prior human smuggling arrest also underscores how seriously Arizona treats that offense. Human smuggling for profit is a Class 4 felony carrying up to 3.75 years in prison, but it escalates to a Class 2 felony punishable by up to 12.5 years if the smuggled individual is an unaccompanied minor, according to Brandon White Law. It remains unclear whether the Maricopa County Attorney's Office will seek additional charges or formally allege Casillas' prior felony convictions to trigger those mandatory sentencing enhancements when he appears in court on August 27.
Maricopa County procedures required Casillas to appear before a judicial officer within 24 hours of his arrest, which is how his $250,000 bond was set so quickly, per guidance from the Nova Law Group. Because he remains in custody, court rules generally require felony defendants held on bond to receive a trial date within 120 days of their initial appearance unless extraordinary circumstances justify a delay, according to the Maricopa County Attorney's Office.
Case Unfolds in a Fast-Growing Corner of Chandler
The apartment complex where the alleged assault occurred sits within Chandler's Price Technology Corridor, a commercial and residential hub near Loop 101 and Loop 202 that anchors much of the East Valley's tech-driven growth, according to real estate data from Redfin. The area has drawn major technology companies, data centers, and dense new housing in recent years.
The case also comes amid a broader decline in reported sexual assaults across Chandler. Arizona Department of Public Safety statistics show reported sexual assaults in the city dropped 54% in 2024 to 51 incidents, part of an overall 23% annual decline in local violent crime, according to the Chandler Independent. Chandler, the fourth-largest city in Arizona, is policed by 348 sworn officers across 18 patrol beats serving roughly 288,000 residents, per the Chandler Police Department.
