difference. >> thank you for the footage, for the video. >> reporter: she survived. eric garner did not. in his case, the video shows the unarmed man being placed in a chokehold by a new york city police officer, but the grand jury decided not to indict the officer. in so many cases of alleged police abuse of power, videos like this are proving to be key pieces of evidence. atika scubert, cnn, new york. coming up in our next half hour, our gary tuchman compares the video evidence of the shooting of walter scott to the initial reports of the other officers on the scene and there are quite a few discrepancies. satisfaction, a step forward, those are just some of the feelings boston marathon bombing survivors say they have, now that a jury found dzhokhar tsarnaev guilty of all 30 counts he faced. but the case isn't closed just yet. chris welsch reports.