An increase in crime witnesses who give information to police has led to 19 homicide arrests in the last two weeks, departing Philadelphia Police Commissioner Sylvester Johnson said yesterday at a news conference at Police Headquarters.

Johnson, whose last day is Jan. 7, praised the "great cooperation" among the FBI, the Homicide Fugitive Task Force, and the Police Department as another contribution to the arrests.

Jayne Challman, FBI assistant special agent in charge in Philadelphia, labeled the arrests "a tremendous Christmas present to the city."

Capt. Michael Costello, head of the Homicide Unit, said he didn't have hard numbers on how many people had come forward with information for the arrests. He did say, however, that the department logged more than 400 calls after Officer Chuck Cassidy was murdered Oct. 31.