LINCOLN, Neb. (AP) — A second Lincoln police officer has resigned amid allegations related to a sexual assault investigation involving another officer.

Lincoln Police Chief Jeff Bliemeister says the second officer was placed on unpaid leave as a result of an internal investigation into the sexual assault allegation. Bliemeister says the second officer was put on leave on suspicion of violating the department’s code of ethics, and that he resigned earlier this week. The chief says the second officer has not been accused of any criminal wrongdoing.

Bliemeister did not release any details of what the officer is accused of having done.

Last month, another officer left the force after being accused of sexually assaulting a woman he met while on duty. That criminal investigation continues.