Commissioner Raymond W. Kelly’s top intelligence official handed in his resignation this month, part of an expected series of changes at the top of the New York Police Department as William J. Bratton prepares to take the helm in January.

The official, David Cohen, had been deputy commissioner for intelligence since the role was created after the Sept. 11 attack, and he was central to Mr. Kelly’s efforts to create a robust intelligence operation in the Police Department.

Mr. Cohen came to the Police Department after 35 years at the Central Intelligence Agency, including two years overseeing its worldwide espionage efforts.

The department’s deputy commissioner for counterterrorism, Richard Daddario, is also resigning. His position was also created by Mr. Kelly.