the way of a romantic rendezvous that he so desperately wanted with nathan. reporter: on november 4, 2009, eight weeks after shelley s murder, they arrested daniel willyam. the arrest was, for shelley s family, a double edged thing. they were relieved, of course. but until then, the police had not told them that shelley had been stabbed 42 times. oh my god, i almost passed out. 42 exact. and i just thought, oh my god. reporter: prosecutor dewey mitchell got the case then, and right away, could see the problem. this was a circumstantial case, in which the accused would likely say, the other guy did it. especially in a case like this. reporter: so he sent out his investigator, hoyt hoffman, to second guess the police. you have to make sure that no stone is left unturned. reporter: and then, they strategized we spent i would say half of
the crime scene. when all these facts comes together, there s no other suspect. and the reason that shelley was killed is because she stood in the way of a romantic rendezvous that he so desperately wanted with nathan. reporter: on november 4, 2009, eight weeks after shelley s murder, they arrested daniel willyam. the arrest was, for shelley s family, a double edged thing. they were relieved, of course. but until then, the police had not told them that shelley had been stabbed 42 times. oh my god, i almost passed out. 42 exact. and i just thought, oh my god. reporter: prosecutor dewey mitchell got the case then, and right away, could see the problem. this was a circumstantial case, in which the accused would likely say, the other guy did it. especially in a case like this. reporter: so he sent out his investigator, hoyt hoffman, to second guess the police.