the witness, washburn.they were scattered all over the country, with the fbi's help, one by one, she tracked them down. >> we asked people. knocked on their door. literally, told them we were investigating a cold case and we'd like to eliminate you as a potential suspect. would you give us your dna? we had, in total, about 160 people that we got dna samples from. >> 160 samples. they all needed to be compared with the dna samples from the two crime scenes. easier said than done. isn't like the movies. this would take months. no idea if any of it would pay off. >> coming up -- so, first batch goes out there. none of these guys were a match. then, i send the next batch out and it's the same thing. >> weeks. months. a year of dead ends. then, came the phone call. >> i was like, no way. >> when "dateline" continues. you'll find a better life. it all starts with the most innovative technology. like the new miracle-earmini, available exclusively at miracle-ear. so small that no one will see it, but you'll notice

but it was actually john nanette, again, let miss george washburn. well, would you allow them to me the like you know, the whole and the the sort of the get through for us not it's none at all. and i, me can about my going to be me. does it had honor that for him comes to the bottom with the because the likely that i did know con, low in just ready go on, move hammock. ah, i'm going to reach the sourcing of the time the report. paragraph, one of us authorities say, call them one still us officials said, said one us justice department counterterrorism official column 2 officials said to us authorities say us official said those officials said the officials confirmed american officials complained. they said us official us officials, crest column 3 us authorities, said jordanian official said no law to please we haven't finished yet. several us officials said call them for us. official said, several american officials said officials say, say us officials, but us and who said one us counterterrorism official said i'm not joking where it is. that is the j

reporter: that is the principal at washburn elementary in windsor, whereas the kids grabbed lunch, theya race against time. it is an adaptation prompted by a day last month when two covid exposures forced them to close down an entire grade level. >> kissing seemed irresponsible for us not to address it. -- it seemed irresponsible for us not to address it. that is a lot students out. reporter: students now get a grand total of 14 minutes in which to remove their masks and eat. you might wonder why 14 minutes -- it seems like an odd number -- but there is a reason for it. state guidelines mandate full quarantines after an exposure at 15 minutes. 14 minutes gives them one minute to spare. >> by doing this for 14 minutes, we can accurately say to the department of public health that we know our students have not been unmasked and within six feet," to, for more than 15 minutes. -- six feet, close more than 15 minutes. reporter: they still treat lunch time as the greatest risk of infection. each child has a seat notated by pieces of tape, so they know who sits next to who. since doing that al

reporter: that is the principal at manny washburn elementary school in windsor.o prepare for a race against time. it is an adaptation prompted by day last month >> >> and covid exposures force them to close down an entire grade level. it seemed air responsible for a stop to address it. it is a lot of students out, it is the full to learn from him. . reporter: you might wonder why 14 minutes, seems like an odd number. there's a reason for it. state guidelines mandate full quarantine after exposure at 15 minutes. 14 minutes gives them one minute to spare. >> by doing this for 14 minutes, we can accurately say to the department public health, we know our students have not been unmasked and within six feet," for more than 15 minutes. reporter: by then, the district had already determined that lunchtime poses the greatest risk of infection. they still treated that way. every child has an assigned seat. they know who sits next to who. 14 rates have dropped f f almost 317 kids last month to just seven students today. >> quarantine to modified quarantine, keeping our kid