AKRON, Ohio -- Akron police Chief James Nice has resigned from his position, city officials said Sunday.

Nice resigned at the request of Mayor Dan Horrigan, a news release from the city states. It does not give a reason as to why Horrigan asked Nice to step down.

Horrigan appointed Akron police Maj. Kenneth Ball to serve as the provisional police chief, the release states.

No further details about the resignation were released Sunday evening. Horrigan's chief of staff, James Hardy, said the city would not provide further details tonight.

Horrigan plans to hold a news conference at 12:30 p.m. Monday to address the situation, the release says.

Nice's resignation comes two days after 17-year-old Xavier McMullen died of a gunshot wound to his head while in police custody. McMullen was sitting in the back of a police cruiser about 11 p.m. Friday after he was detained in connection with a robbery.

Shortly after he was placed in the patrol car, Akron officers heard a gunshot and saw that McMullen was shot. Authorities found a gun near the teen, the Summit County Medical Examiner said in a Saturday news release.

During their preliminary investigation, police learned that McMullen likely shot himself, but it's still unclear if the shot was intentional or accidental, Akron police spokesman Capt. Daniel Zampelli said Saturday.

Two other men -- Anthony Criss, 18, of Cuyahoga Falls and Matthew Allen, 18, of Akron -- were arrested and charged with aggravated robbery in connection with the incident, Akron Municipal Court records show.

Akron police's Office of Professional Standards, as well as the medical examiner and the detective bureau, continue to probe the incident.

This is a developing story. This post will be updated.

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