New Haven Police Department Chief Frank Limon will resign this November after a tough 18 months in the top job.

Mayor John DeStefano Jr. announced Limon’s resignation, effective Nov. 15, at a press conference at City Hall Monday afternoon, ending speculation that erupted over the weekend following reports that Limon had cleared out his office and New Haven condominium in advance of a trip to Illinois that started Friday. DeStefano said that Limon’s departure was the result of a mutual agreement and that he had no cause to dismiss the chief.

“[The decision was reached] after two weeks of discussions regarding [Limon’s] personal circumstances and goals for the department,” DeStefano said at the press conference, adding that he will announce Limon’s replacement at a press conference 3 p.m. Tuesday.

Limon will continue his contractual relationship with the department through June 2012 as a consultant, DeStefano said, continuing some of his ongoing projects. He added that Limon will earn $90,000 during this time, compared to his salary of $150,000 as chief.

Much attention Monday focused on the secrecy behind Limon’s departure. As of Sunday evening, both City Hall spokesman Adam Joseph and NHPD spokesman David Hartman stressed that Limon was still police chief. According to Hartman, Limon was originally scheduled only to travel to Chicago for the Conference for International Association of Chiefs of Police, which runs Oct. 22-26.

Mayoral candidate Jeffrey Kerekes and former NHPD union president Sgt. Louis Cavaliere, however, said they received multiple reports from officers that Limon’s departure was permanent.

The lack of transparency regarding the nature of the chief’s trip bred both media speculation and rebukes from police union leaders.

“My concern, like that of a lot of other people, is why the city didn’t handle the information [of Limon’s departure] properly,” said NHPD Union President Arpad Tolnay in an interview Monday before DeStefano’s press conference. “I’m going to step out on a limb and say, if this is a small peek at how politics is conducted here in New Haven, then maybe it’s time to switch things up.”

DeStefano defended his reluctance to make the chief’s resignation public, saying that he acted as he saw fit. But he said that “speculation had become so rampant” that he felt it would have been a mistake not to announce Limon’s departure Monday.

Limon’s resignation marks the end of a difficult tenure.

When Limon first arrived in the Elm City from Chicago on April 5, 2010, he brought two assistant chiefs along with him from his old department. This unfamiliar leadership, coupled with what some union leaders called an “abrasive” managerial style, led to tension within the department. Calls for Limon’s firing peaked with the NHPD Union’s Feb. 3 landslide no-confidence vote against him, with members citing departmental mismanagement and inability to connect with rank-and-file officers. Since he began as chief, Limon has presided over a 9 percent reduction in the Elm City’s overall crime rate this year, even as New Haven is seeing its deadliest year since 1994 — the homicide count for 2011 sits at 27.

While officials at City Hall refused Sunday and Monday to disclose details about the new chief being announced today, speculation has centered on a former NHPD assistant chief.

Dean Esserman, a former Providence Police Department chief and NHPD assistant chief, is slated to take over as NHPD chief, one “knowledgeable source” told the New Haven Independent Monday afternoon. When asked by the News whether Esserman was in contention to replace Limon, Tolnay said he had heard the name discussed. Tolnay added he was unsure about other individuals in the running for the chief’s job.

Following Monday’s press conference, Kerekes, who is running to unseat DeStefano in the Nov. 8 mayoral election, said that DeStefano was improperly secretive about Limon’s departure and the city’s preparations to search for his successor.

“It’s a credibility issue,” Kerekes said, adding that neither the public nor the Board of Aldermen had a say in selecting the new chief.

Ward 12 Alderman Gerald Antunes, who serves as vice chairman of the city’s public safety committee, said the Board of Aldermen has not yet been given information about Limon’s replacement. He said his committee had expected the chief to resign for some time but declined to say how long he had known about the situation.

Adam Joseph, City Hall spokesman, said the mayor and Limon decided upon Limon’s successor in the past two weeks, but declined to say whether it will be an external or internal pick.

Current Assistant Chief John Velleca will serve as the department’s acting chief until Limon’s resignation in November, DeStefano said.

Yale Police Department Chief Ronnell Higgins said he was similarly in the dark about who the mayor has picked to run the NHPD. The impact of the new NHPD chief on the University police force will be negligible, he said.

“When I learned the news [of Limon’s departure], I immediately called the acting chief and stressed our commitment to working with him and he expressed the same back to me,” Higgins said.

University President Richard Levin said Monday night that the University and its police department will cooperate closely with whomever is chosen to replace Limon, adding that he had not been made aware of the chief’s impending departure.

Velleca currently heads the NHPD’s investigative services division.