finally slipped up. here's abc's clayton sandel. >> reporter: there he was again, in one hand a note demanding cash. in the other a gun. the teller gave him the money and something else. a hidden dye pack that exploded as he left. >> quite a bit of money in the parking lot spread out every several parking stalls. not sure if he got away or not. >> reporter: the geezer bandit also dropped what is believed to be a small address book. potentially a big break for police. >> they may get lucky and get fingerprints off what he dropped. you might not be able to identify him, but you might be able to link him to other robberies. >> reporter: investigators won't say how much he has stolen. nationwide last year the average take for robbing one bank was over $8,000. friday's bank job is his 16th in southern california. he stayed one step ahead of police, being careful to vary locations times and days of his robberies. with each new heist the pile of surveillance, video and news coverage grows.