and there's conversations going back and forth. >> when detectives tracked the cellphone movements, they could see whoever was talking to sarah started off in mastic, new york. then traveled about ten miles north to where sarah was living near eagle estates. >> she's home. but we see this phone number, this cell instrument with this phone number move very deliberately right up to sarah goode's home, where the phones come together. >> once the cell phone pinged near sarah's house, all phone communication stopped. prosecutors believe that's when sarah and her caller started communicating in person. >> she receives a call from a young man, and at 1:30 in the morning, you know, she went out to meet him. >> albertson theorized sarah, who was 21 and a single mom, wanted to make the most of this rare night out.