District A-1’s police community liaison has been transferred after two years on the job, much to the disappointment of neighborhood leaders.

District A-1 includes Beacon Hill and Downtown.

Sergeant Zachary Crossen, who took on the position of A-1 liaison in September of 2023, made quite an impression on the neighborhood in his short tenure. It is unclear where he will go.

“He was very good,” said George Coorssen, a leader of the Downtown Boston Neighborhood Association (DBNA). “He was the go-to guy. Best guy we’ve had in A-1 in his position that I remember. I worked with him about at least once a week, and we had lunch together at least once every other week. I have nothing but praise for his presence down here. He’ll be greatly missed.”

Michael Nichols, president of the Downtown Boston Alliance, also praised Crossen’s work.

“Sergeant Crossen was a terrific partner in supporting the community in making our area safer throughout his time Downtown,” Nichols said in a statement.

“He helped spearhead the launch of several new initiatives and was a tireless presence in ensuring effective communication between BPD, our organization, Downtown business owners, residents, and others. We thank him for his service and wish him well in his new assignment elsewhere in the city.”

Crossen will be replaced by Sergeant Sean Wallace, according to an announcement by the Downtown Boston Alliance on Tuesday. Wallace has been in the force since 2015, and was most recently a detective in district D-4 in the South End. He was promoted to the rank of Sergeant in November of last year, according to state records.

Crossen was heavily involved in a number of initiatives around Downtown, Coorssen said, from general public safety concerns to electric scooters to drug use.” Anything that was an issue in the Downtown Crossing, he would deal with it,” Coorssen said. “He helped make it better.”

That work included the public safety summit organized by the DBNA in February in response to rising complaints of open-air drug use in the neighborhood. Some of the 92 officials at that summit included Mayor Michelle Wu, Suffolk County District Attorney Kevin Hayden, and numerous city and state representatives, as well as District A-1 Captain Richard Driscoll.

The BPD did not respond to a request for comment asking where Crossen will be stationed next.