Diligent police work can lead to tremendous results. We were following up on a lead about a parking ticket in the neighborhood where one of the murders had just taken place. It turns out, when calling through the switchboard, the operator knew David Berkowitz and mentioned that he had exhibited some strange behaviors. All this information and this random parking ticket lead helped to assist us in finally taking this killer off the streets.
While in the NYPD he joined the Army Reserve, entering at the rank of Staff Sergeant and retiring in 1989 as a Major.
Clark joined the New York City Police Department in 1969. He worked a special undercover assignment for two years before entering the Police Academy. In 1972 he earned his gold detective shield. On December 31, 1994, Clark retired from the Queens Homicide Detective Squad as a First Grade Detective.
He co-authored, along with NYPD Blue co-creator and Executive Producer David Milch, True Blue: The Real Stories Behind NYPD Blue (1995.)
Activision consulted with Clark on their 2005 release True Crime: New York City.
His first assignment—even before he attended the Police Academy—was to infiltrate the Young Patriots Organization, an organization of white radicals who, he soon discovered, were planning to bomb several New York City landmarks.
At age 17, Clark joined the United States Army, with tours of duty in Europe and Vietnam as a member of the Infantry Division where he served as a scout dog handler, walking point with his German Shepherd Dog Mox, with the Forty-Sixth Infantry Platoon Scout Dog, Second Battalion, 14th Infantry Regiment.
