A 20-year-old California college student used a popular Snapchat filter to nab an alleged sexual predator.

Oh, and that alleged sexual predator just happened to be a San Mateo police officer.

Ethan used the recently popular gender-switch filter on Snapchat to become "Esther." He made a Tinder profile posing as 19-year-old Esther and was contacted by a male user.

I believe he messaged me, 'Are you down to have some fun tonight,'

San Mateo Police Officer Robert Davies thought he was talking with Esther, who told him that she was 16, and according to NBC Bay Area, a San Jose Police report says that "Davies acknowledged." Davies also asked Esther to switch over to Snapchat where her being 16 years old was also discussed.

Soon the conversation turned sexual, getting very explicit according to Ethan, who chose not to reveal his last name in fear of retaliation after he released Davies was a police officer. Police served search warrants on Davies' electronic devices, mobile apps and at his home.

He was arrested on suspicion of contacting a minor to commit a felony and booked into the Santa Clara County Jail. According to the San Mateo Police Department, Davis has been placed on administrative leave according to a statement from the department.

This alleged conduct, if true, is in no way a reflection of all that we stand for as a Department, and is an affront to the tenets of our department and our profession as a whole.

As far as why Ethan set up Davies, he says he was just "looking to get someone. He just happened to be a cop."