Innocent Blood (VHS, 1993).

Marie is a vampire with a conscience: She only sucks the blood of criminals. And she has plenty to choose from on the mean streets of Pittsburgh, where a gang war is raging. But Marie slips up when she accidentally turns a violent crime lord, Sal Macelli (Robert Loggia), into one of the walking dead. To stop a takeover of the city by blood-sucking gangsters, Marie joins forces with an undercover cop (Anthony LaPaglia) who has his own score to settle.