The crazed, knife-wielding woman who allegedly killed a USPS worker for skipping her in the deli line spit in the victim’s face before the fatal knifing, a witness told The Post. The worker who was manning the grill said multiple customers tried to separate the pair after accused killer Jaia Cruz started a verbal argument.

The suspect charged with killing an on-duty postal service employee reportedly has a violent criminal history, according to news reports.

The woman accused of stabbing a postal worker to death over a spot in line at a Harlem deli has a long history of knife violence — and once threatened “to cut” one of her previous victims.