The Regional Crime Laboratory ballistics analysis indicated that while Fred Schultz's service revolver, a Smith & Wesson .38-caliber revolver with a four-inch barrel, showed traces of blood, type A, which was consistent with the victim (and him), the 200 grain bullet, fired from his off-duty .38 Smith & Wesson snub-nose revolver with a two-inch barrel, proved that the killer had access to that gun. The markings on the slug matched markings in the gun barrel.
Fred Schultz, Judy Zess, Thomas Gaertner, the landlord, and Lawrencia Bembenek all had keys to the apartment and thus had access to the murder weapon, although Bembenek was there alone allegedly sleeping when the murder occurred.
Not long after the murder, a reddish-brown wig was found clogging the plumbing of the apartment across from that in which Bembenek and Schultz resided. The wig hair was consistent with a hair found on the victim's body. The apartment shared a y-shaped drainage line leading away from two apartments, the one occupied by Schultz and Bembenek and the one across from them.
A hairbrush owned by Bembenek was sent to the crime lab and they noted that at least one hair from the brush was consistent with a strand of hair found in the gag over the victim's mouth.
In the end, Bembenek was charged with the crime, since she had access to the weapon determined to be the gun that killed the victim. She was arrested on June 24, 1981. At first she was stunned, claiming she was innocent, and then she insisted she was being framed by the police department to stop her from releasing evidence she had of their fraudulent use of government funds. She was sure her arrest would come to nothing and she would soon be proven innocent.