When there are two verbs, it should be made clear who is the subject and object of both actions, else it lacks ideal clarity. Here, the men are presumed to be the same that robbed the bank, and the seen is not attributed to an observer, which is an slightly improper enunciation of an observation.
It is not an ideally clear sentence, and it sounds like an ad-lib report, like a news report, written hastily in informal English, it sounds like a summary of a phrase, rather than a clear phrase.
"seen by whom? where? doing what? running? climbing?"
Generally, if a phrase lacks clarification, it sounds like a quoted and spoken phase, rather than a clearly written narrative.
It's out of context, the rest of the phrase may give it some clarity. On it's own, it's a bit unclear.