Croyle said Boehme told detectives that he and Mills were friends, but had gotten into an argument over undisclosed issues that culminated in gunfire.
An autopsy performed by the state Medical Examiner's Office determined the victim had multiple gunshot wounds to his body and that the manner of death was homicide, Croyle said.
Detectives had received information that led them to Boehme's whereabouts, but further details on the investigation and arrest were not immediately released.
Ogden police had identified Boehme as a suspect not long after the body of Mills was found in the storage unit at 2930 Pennsylvania Ave. last week.
The suspect's vehicle, a red 1989 Ford F-150 pickup truck, was later found abandoned in west Weber County.
Boehme has a substantial criminal history, mostly drug-related convictions, according to a search of Utah court records. His most recent conviction was in 2009, where he pleaded guilty to driving on a revoked license and having a "speed contest" on a highway, and several drug-related charges were dismissed. He was ordered to complete drug court in that case, according to court records.
Court records indicate that Mills was released from the Davis County jail on April 11, after being convicted of violating a protective order, interfering with an arresting officer and failure to stop at the command of police.
Mills' other recent criminal history revolves primarily around multiple protection order violations over the last six years, according to court records..