. >> alicia: we are going to bring in maryellen a o'toole. thank you so much for being here. let's talk about the investigations, we are still awaiting this news conference to find out exactly what led police to the suspect. what role do you think the forensics blade, dna played in all of this? >> my sense right now is forensics played a big role in this. the fbi to make an arrest, on these charges, they had to have something that was very compelling, significant. in a case like this it would be forensics and probably dna. as he reported over and over again this crime scene had a lot of forensic evidence left at the scene. it had to be more than hairs and fibers. it had to be something significant. my senses right now, i could be wrong, my sense is it's going to be dna evidence. >> gillian: to that point, up until now when we learned of the arrest and the indictment as far as when police did not have a murder weapon. you think they are going to announce they have located one at this press conference at 4:00? >> i think if they found it and they could connected to the scene, i

molly: let's bring in maryellen o'toole, director of the forensic science program at george mason university. thank you for giving us time this new year's eve. in the wake of this arrest and your profiling experience, from what we know about the suspect, is this the type of person you inspected to be arrested in this case? >> there is so much more we need to learn about him and there's no one box these offenders go into so they are all studying at school, they are all a certain height, a certain weight, so they never matched particular profiles so you have to go point by point by point and in this case, one of the most interesting things is this suspect was able to blend back into her social life after the homicides and that is important because after a homicide like this, the general public tends to think of someone that looks like freddy krueger, someone who's very scary looking, who appears to be more like a monster. more often than not, when offenders are arrested, people will comment they don't look like they could have done something like that or i live next door to them and i thought