in 2004 detective siler called john lewin, a prosecutor with the l.a. d.a.'rimes division. lewin specializes in cold cases. >> they had collected originally the fingernail scrapings. they had collected the blood, and detective eniard had been unable to get the lab to test it. so when i first got on the case i started trying to cash in favors at the crime lab to get it done. >> but a ten-year-old cold case was not a priority. three more years passed before those samples were tested. finally in november, 2007, the fbi crime lab came through. >> what we got was the information that would break this case wide open. >> a new clue triggers a bold move from the cold case prosecutor, and someone close to marie is in for a surprise. >>> coming up. >> it was very hard. i had to have marcus arrested. >> marcus, marie's own son, under arrest? when "dateline" continues. when eye allergens attack, the itch can last 24 hours. but with pataday once daily relief extra strength you get fast, 24-hour relief in one drop. make it a pataday with the drop that's right for you. now

joining us now to talk about why that charge is professor jonathan siler. vasser, thank you for joining us. >> my pleasure. the essence of second degree manslaughter is that you have caused the death of another person by doing something dangerous, in a way that departs from the reasonable standard of care. >> and how does the prosecutor then, in this case, for instance, come to this charge? >> well, i think the important point here is this an unintentional homicide. the prosecution is not claiming that potter intended to kill. what they are claiming is that potter's action was a huge to partner was what a reasonable police officer would have done. so much so that even if she didn't intend to kill, we can still treat it as a very serious crime with up to 10 years of imprisonment. >> what is the difference to clarify even further between second degree and first degree? >> first degree manslaughter in minnesota, and many states, is when you kill intentionally but under great emotional disturbance or provocation. it is quite a different approach. what we have s

minister siler subsequently claimed what he wanted was to simplify the existing rules. and president bolsonaro's government certainly appears to be dismantling some of the structures that had succeeded in holding back destruction in the amazon. the environmental police force, is on the front of brazil's efforts to protect the forest. but some officers say they aren't getting the support from the president that they need. one of them agreed to speak to us anonymously. translation:— to speak to us anonymously. translation: , ,., translation: over never seen so many illegal— translation: over never seen so many illegal goldmines. _ translation: over never seen so many illegal goldmines. the i many illegal goldmines. the price of gold is higher than ever. the perspectives used to be scared, now the feel the president will protect them —— prospectors. in places where we didn't have incidents in the past, now loggers, prospectors and rioters are there. an officer got hit with a bottle. the police are loyal to the president. are used to give security to operations. the brazili