>> help, somebody's in my house. i have a baby downstairs. >> we got a child downstairs and she's upstairs. >> the intruder reaches melissa's bedroom as she continues on the phone. >> they're going up the stairs. melissa, stay on the line with me, okay? do you hear police? [ screaming ] >> you got to get in there! >> police! >> get off that bed! get off that bed right now! >> he has a knife! >> police catch deric allen. melissa and her baby daughter are both safe. >> she could have been killed. i mean, without question. if she didn't stay on that phone, absolutely, she could have been killed. >> when melissa's dad first hears the 911 call, he's