Nassau police are linking 28 of the 74 bank robberies so far this year to four heroin users.

Bank robberies are up more than 50 percent in Nassau County this year, an increase authorities are attributing to a handful of serial robbers who have stolen money from multiple banks, including four heroin users stealing to pay for their costly habit.In New York City, robberies also are up more than 50 percent, a spike authorities attribute to banks having longer hours and more customer-friendly features, such as no Plexiglas or barriers.While an ailing economy may be sparking the rise, Nassau police are linking 28 of the 74 bank robberies so far this year to four heroin users. The drug's use has been a growing problem in a county where teenagers have died from heroin overdoses in record numbers and lawmakers have proposed legislation to combat the problem."There is definitely a recognizable increase in heroin use among our bank robbers," said Det. Sgt. John Giambrone, commander of the Nassau police robbery squad. "Several serial bank robbers were doing it to support their drug habits."