A Florida police officer, once declared “Officer of the Year” by his former department, was arrested by federal authorities this week for allegedly sharing—while on duty—images of children being sexually abused.

Michael Harding, employed by the Port St. Lucie Police Department since 2012, faces federal charges for receiving and distributing material involving sexual exploitation of minors and possession of child pornography.

Homeland Security investigators began monitoring Harding in July, when an undercover agent discovered his alleged account on the Kik Messenger service uploading images of underage girls engaged in sexual acts. Harding is accused of sharing the photos under the username “desthfromabovee.”

Authorities believe he uploaded some of the child-abuse content while sitting in his patrol car.

An undercover investigator said that “desthfromabovee” shared two of the images during their first encounter online and posted more photos a week later, according to a criminal complaint. In August, “desthfromabovee” also allegedly posted an explicit video of a young girl engaged in a sexual act.

A local CBS news affiliate, which spoke to the authorities involved, reported that some of children in the photos were “barely out of diapers.”

Homeland Security tied the “desthfromabovee” account to Harding after obtaining phone records from AT&T, which helped them link his IP address and cellphone service to the Kik account. According to the criminal complaint, Harding went by the full name “Mark Powers” online.

Harding allegedly used the Kik app 33 times, typically between midnight and 6am. Based on the time frame and Harding’s overnight work schedule, authorities believe he uploaded some of the child-abuse content while sitting in his patrol car.

Investigators reportedly found two thumb drives in Harding’s home, one of which was stored in a gun case in the master bedroom. Police say it contained hundreds of images and videos of children “engaged in sexually explicit conduct,” according to the criminal complaint. The second drive included photos of Harding and “bondage photos of prepubescent girls,” according to law-enforcement authorities.

Harding was formally charged in court Wednesday morning. If convicted, he faces a minimum of five years and a maximum of 20 years in prison.

H/T CBS 12 | Photo by Jon Candy/Flickr (CC BY SA 2.0)