Prosecutors are accusing a Minneapolis police sergeant who once worked as security to Mayor Jacob Frey with stalking and harassing a former romantic partner — a fellow police sergeant.

Gordon L. Blackey, 59, was charged Wednesday with harassment and unauthorized use of a tracking device — both gross misdemeanors — and two counts of misdemeanor unauthorized acquisition of nonpublic data.

Blackey admitted to investigators that he tracked the woman's movements by placing Apple AirTags on her vehicle and used a state database accessible to police officers to look up personal information for the woman's father and co-worker, according to the criminal complaint.

The victim told investigators that Blackey's actions gave her anxiety, led to sleep loss and affected her work performance, the complaint said.

Blackey has been with the department for more than 27 years. He served as Frey's driver and bodyguard until May of this year and was often seen alongside or not far from him at public events inside City Hall and out in the community.

Blackey's complaint history dates back to 1998. Internal discipline records obtained by Communities United Against Police Brutality, a police watchdog group, show that the veteran officer has been the subject of at least 11 complaints. None resulted in formal discipline.

He has one current open complaint, according to the city's complaint dashboard.

A spokesperson from the mayor's office said Frey takes the charges seriously and that security details are assigned by the police department.

"I am, of course, very concerned about the charges, but I'll refrain from commenting further to maintain the integrity of the criminal legal process," Minneapolis Police Chief Brian O'Hara said in a statement.

Robert Jones, Blackey's attorney, told the Star Tribune that his client has cooperated with law enforcement and has a "pristine record" on the force.

"He's a good cop — that's why I'm helping him out," said Jones, who declined to confirm Blackey's employment status. "There's a lot more that will come out. … If you know him, what they're painting him out to be is not him.

"I'll tell you right now: He's not going to plead guilty to something he didn't do. Plain and simple."

Jones noted that the woman in this case was not a subordinate, but a colleague of the same rank.

"It's a not a power differential sort of thing; they did have a relationship," he said.

According to the criminal complaint:

The victim first noticed an AirTag was placed on her vehicle in March when, as she was leaving her home in Anoka County, her daughter's phone received a notification about the presence of the device.

The victim found the device on her vehicle's wheel well, and its serial number was linked to a phone number she recognized as Blackey's.

About one year before the discovery, Blackey and the woman engaged in a brief romantic relationship. The two maintained a professional and friendly relationship afterward.

Wanting to avoid issues at work, the victim told Blackey she no longer wanted to be around him and did not pursue further action.

Less than two months after discovering the tracking device, in late April, the victim declined an invitation from Blackey to get a drink, the complaint said. Later the same evening, she went to a restaurant with friends and saw Blackey there as well. She began to recall past incidents where she ran into Blackey unexpectedly and when he displayed knowledge about her life.

Days later, the victim reported the incidents to the Anoka County Sheriff's Office. Investigators found records showing Blackey purchased the AirTag from a store in Roseville and was not authorized to use it to track the victim.

His iCloud account also contained photos of a computer screen displaying private driver's license information, which appeared to be obtained from a state database accessible to police. Records from the Minnesota Bureau of Criminal Apprehension confirmed Blackey used the database to access information about the victim's father and co-worker, with no law enforcement purpose for doing so.