dr. lawrence kobilinsky, a forensic scientist and professor at john jay college of criminal justice. thank you for being here dr. kobilinsky. >> sure, good evening. >> could someone -- i need to know this -- could someone have broken their own neck like this? is it physically possible? >> no. i would say that it is not possible. you would need to exert a very strong force, an impact in a particular area that would affect the vertebrae and fracture them. i think, i would say, that certainly, in the van, if he were alone, he could not create those fractures. >> now, there's a local tv station, dr., in washington claiming that a head injury on freddie gray matches a bump in the van. what do you make of that? >> you know i think there are two issues here. i think the -- we know about the fractured three vertebrae, we know about the spinal cord that was severed about 80%. and i think given what we have observed when they dragged him to the van, it seems to me that the initial injury occurred during the struggle with the police during that takedown perhaps a knee on the neck. i mean that co