let's get into the business of beveling. beveling, as we pointed out here, occurs when the bullet goes through, like abb through a pane of glass. boswell, and this is in my report, boswell told me the same thing he told harrison livingston, and i think in the assassination records review board, he said they had to dissect jfk's scalp and the skull bone, but "not too much because the bone was all gone and the smallest fragments fit this piece down here. only was a whole here, half of which was present in the bone that was intact, and this small piece then fit right on there and the beveling on those was on the interior surface." what he is saying is this suggests there was an intact plate of bone that he took out of the brain that looked inside inside that intact plate of bone, there was a beveled wound. that was not what it was at all. what he is saying is what there was was an edge of a bone and another fragment was wrought in later and fit in. when you put the two together, you could make out that there was perhaps bevelin

behind because it was beveling. there was also the new york decidingming in and that was a boring in the rear of the neck that had proved a bullet had gone in for behind. let's get into the business of beveling. beveling, as we pointed out here, occurs when the bullet goes through like a bb per a glass. this -- butell at to win a boswell and this in my report, boswell told me -- but when boswell edits is my room --ards, boswell talk they had to what he is saying is this suggests that there were an intact plate of bone that he took out of the brain that looked inside and inside was a beveled wound. that was not what it was at all. what didthere was -- there was was an edge of a bomb and another fragment wrote in. -- what there was was an edge of fragment. another owns supported by his autopsy sheet and it could go back to the level -- or you do not have enough skull if you look at the bottom. , this is small little diagram of something, this bone was all gone. small piece fit this is the autopsy sheet. the absence of

. >> the character of the hole through the skull, that it was bevelled on one side, and not as bevelled on this side. and the fact that this bone is discoloured around it. >> i can see that for sure. >> it's more indicative that that is a gunshot wound. >> reporter: if the bones are needed as evidence in court, the body is skeletonized not by a lab technician, but nature's own cleaning crew. the lab's colony of flush-eating beatles can strip a carcasses clean in a matter of days. you are dealing with kind of the gory details here. do you find yourself being personally impacted by what you see on the table? >> when i see something that indicates that there was suffering prior to death, and they are slowly wasting away and starving, that's when it gets a little hard. if i just think of everything as a stuffed animal, if you will, it makes it a little easier. >> the shock is the few times i have seen the animals grievously harmed, but not dead. the horn ripped off the rin oserrous, but it's alive and moving around, that enrages me. i know that if i can keep this lab team right down the lin

. >> the character of the hole through the school, it's long and beveled on one side and it's not aseveled on this side, the fact that the bone is discovered around it. >> i can see that for sure. >> that's more indicative of a gunshot wound. >> it. the bones are needed as evidence in court the body is galvanized. the lab's colony of beetles can strip a carcass clean in a matter of days. >> you're dealing with the gory details here. do you find yourself ever being personally impacted by what you see on the table? >> when i see something that indicates suffering prior to that, and they're slowly wasting away and starving, that's when it gets hard, but i think of everything as being stuffed animals, if you will. it makes them easier. >> but still pretty hard. joining us now is "techknow" contributor marieta good to see you. >> this is really fascinating stuff. tell us more about this lab and what makes it so unique and who are the people who work there? >> it is the u.s. fish and wildlife forensic lab and it's the only kind of it's kind in the world. this hip in major problems in long-

. >> we have a beveled transition on the change in level, tape on the surfaces, temporary asphalt to fill in level changes, flush transition to temporary wood platform and ramp down into the street under the scaffoldinging. detectable ramps. they are all detectable. nothing down below or protruding that people are going to get snagged up on. smooth clean that nobody is going get caught up on. >> our no. 1 issue is what we see here, the uplifting and shreufting to concrete due too street tree roots. here is another problem we have with street trees. if i have i was a person blind, this would be an uncomfortable way to find out. >> we don't want to create hazards. >> sometimes vendors put sidewalk cafes where people push the chairs too far out. >> sometimes it can be impassable. so much foot traffic that there is no room for a wheelchair or walker to go by. >> san francisco is a lively street life, it can be an issue with people with visual disabilities as well. they have these diverting barriers on other side of this tables and chairs area. if people can find thraeur way around it wit

what insight we have as to where these talks are at come bevels reuters news agency report quoting a source in the european delegation close to the talks who says this, that the chances of a final iran deal by monday's deadline are very small, that there is no significant progress on sticking points around iran's uranium enrichment program and the lifting of sanctions and the discussions on a possible extension of these talks may begin on sunday. now, what exactly that means, we are not clear whether they may talk for a day or two more if they believe a deal is in sight or whether indeed they may break up these talks to return at a future date remains to be seen. >> coming up on the program, as tunisia prepares for a landmark presidential vote, we look at the main contenders, plus action i am harris whitbeck where the government is applying economics to a fight against illegal drugs. >> trying to find out who has the edge going in to the final race of the formula one season. authorities have received a distress signal from a boat carrying hundreds of migrants believed to be syrians s