CHATTANOOGA (AP) — A former Tennessee police officer who admitted to sexually assaulting three women in his custody and using a stun gun on another victim has been sentenced to 20 years in federal prison.

A U.S. District judge sentenced former Chattanooga police officer Desmond Ladon Logan, 34, to the maximum amount possible under his plea agreement on Wednesday, The Times Free Press reported.

Under the September 2019 agreement, Logan pleaded guilty to two counts of deprivation of civil rights connected to two assaults and admitted to two other rapes for which he faced no additional federal charges, the newspaper said. Prosecutors said the agreement held him publicly accountable while sparing the victims a trial.

The FBI and the U.S. Department of Justice's civil rights division began investigating Logan in June 2018. He resigned from his post in January 2019 amid an internal investigation.

Investigators alleged that Logan took three women into custody on separate occasions, and drove them all to isolated locations where he sexually assaulted them. In another encounter, Logan was working security at the University of Tennessee at Chattanooga when he asked a woman to drive him to his car, then later used a stun gun against her and made her fear she would be raped or killed, investigators said.

The U.S. Attorney for the Eastern District of Tennessee said in a statement that officials were committed to prosecuting such abuses of authority.

"The actions of Desmond Logan jeopardized public safety and violated the trust of the citizens of Chattanooga he swore to protect," J. Douglas Overbey said in the statement.

Appearing before the judge on Wednesday, Logan apologized but claimed he "never hurt anyone."