The slaying of actress Rebecca Schaefer by an obsessed fan made a great impression on Pam Dawber. "When you're on a hot show, the crazies come out of the woodwork," Dawber, who starred with Schaefer in the sitcom "My Sister Sam," says in an interview in Redbook magazine. Dawber is especially concerned since she has a new TV show in the works. "I've been left alone for a while because I haven't been in anything new but with my (new) show, it will start over again - the threats, the weird letters," she said. Because of her concerns, Dawber and her husband, actor Mark Harmon, do their best to guard the privacy and won't let their son, Sean, 3, be photographed. "It's scary to think what can happen if Pam signs an autograph `To Joe, Love Pam' and Joe takes it the wrong way," Harmon says.