prosecutt the driver who was arrested here. take a look again -- what critics say these officers forgot is when they start recording on their bodycameras, the system has already saved the previous 30 seconds of video. this is when you see one of the officers appear to put something in the car. then they all step back, the audio starts, the recording officially begins and they find drugs. >> oh my god, i knew it. that's why they were freaking out. >> that's the weed smell right there. >> reporter: same thing happened here, that 30 second preview struck again, in video from another drug bust that led to the suspension of a police officer last month. prosecutors have dropped more than 30 cases connected to the officers in this case, and more than 120 cases are under review. >> we are dismissing those cases which rely exclusively on the credibility of these officers. >> reporter: baltimore's police commissioners are reminding their officers that they need to turn on their bodycameras at the beginning of a call and keep them on, david. >> steve osunsami with us tonight. thank you, steve.