A Minneapolis police officer is in jail after his arrest for allegedly having off-duty sexual encounters with several girls between the ages of 12 and 14, according to the Anoka County Sheriff's Office.

Investigators from the Brooklyn Center Police Department were alerted that Bradley Schnickel, 32, used social media to contact a female and sent inappropriate messages to her. The investigation widened and multiple possible female victims were identified, authorities said. Cmdr. Paul Sommer of the Sheriff's Office declined to provide a number.

Schnickel, of Andover, was arrested Wednesday on suspicion of first-degree criminal sexual conduct with a person under 13 that caused personal injury. He hasn't been charged, but the Anoka County attorney's office is expected to file charges Friday.

Schnickel was placed on paid administrative leave Jan. 24, and Chief Janeé Harteau ordered an internal investigation. He has worked for the department since 2008 and most recently was assigned to the Fourth Precinct, which covers the city's North Side.

During his time as an officer, Schnickel has had three complaints against him sustained by the internal affairs unit. They involved issues of search and seizure, force, and code of conduct, the department said.

Schnickel could not be reached Thursday, and his attorney declined to comment.

The current allegations include sexual contact and penetration, Sommer said. In some cases, Schnickel allegedly only solicited people, he said. Schnickel didn't identify himself as an officer to the juveniles, Sommer said, and the alleged conduct was off duty.

Sommer said he didn't know when the first girl contacted Brooklyn Center police. The Sheriff Office's investigation is "ongoing and fluid," he said.

Sommer declined to detail how Schnickel used social media to contact the girls. In general terms, Sommer said, the officer sent messages to unknown girls and started a dialog with them. Schnickel would then access the contacts of the girls, which would allow him to communicate with other girls, according to the commander.

Harteau issued a statement Thursday saying that "if the alleged criminal charges are true, it is horrific and goes against everything the Minneapolis Police Department represents, our core values and our mission." Earlier this week, she addressed the entire department in person and detailed her vision for its future.

"This should not reflect upon the women and men of this department, who truly want to serve this community with integrity," Harteau said in her statement Thursday.

Several Minneapolis police officers who have worked with Schnickel but were reluctant to speak publicly because of the sensitivity of the case expressed shock.

Lt. John Delmonico, president of the Police Officers Federation of Minneapolis, the union that represents officers, expressed outrage over Thursday's news. Conduct like what is alleged, he said in a news release, flies in the face of everything the federation and its members stand for. He referred to "the work and reputation of hundreds of Minneapolis police officers who do an exemplary job every day."

David Chanen • 612-673-4465