A male, vigilante college student used Snapchat's new gender filter, posing as an underage girl, to nab a police officer seeking to engage in sexual activity with a supposed 16-year-old girl.
The student, identified as Ethan, who wanted to engage in vigilante justice after learning his friend was molested as a child, used the filter to pose as a 16-year-old girl named Esther on popular adult hook up app Tinder.
When he began the profile, he hoped to take down a predator.
He ended up catching San Mateo police officer 40-year-old Robert Davies.
"I was just looking to get someone," Ethan Said.
"He just happened to be a cop."
Officer Davies described his intention to engage in sexual activity with "Esther" in messages back and forth between the account.
"I believe he messaged me, 'Are you down to have some fun tonight?' and I decided to take advantage," Ethan, who did not want to give his last name out of fear of retribution, told NBC.
Davies initially messaged Ethan in early May before the two eventually moved their conversation to the messaging app Kik.
He was arrested June 6.
Screenshots of their conversations show that Davies was still interested in engaging in sex with the girl, even after discovering she was 16 (the profile said 19), according to Fox News.
"We started texting on there, and it got a lot more explicit," Ethan said of about 12 hours worth of chats on Tinder, Kik and Snapchat.
Ethan deliberately got enough of officer Davies' personal information to track him. He even switched to airplane mode to prevent Davies from receiving alerts notifying him when screen shots were taken on the SnapChat app.
San Jose police say those screenshots show Davies "chatted about engaging in sexual activity" and led to his arrest last Thursday after search warrants were conducted on his home and electronic devices.
Officer Davies was booked into the Santa Clara County Jail on charges of contacting a minor to commit a felony and put on paid administrative leave.
"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," San Mateo Police Chief Susan Manheimer, said in a statement.
Ethan insists his vigilante days are behind him, according to the New York Post.
Davies bond was set at $50,000.
The San Mateo Police Department issued a statement saying officer Davies has been placed on paid administrative leave.