The Stool Pigeon (1915)

Walter Jason, a young man from the country, comes to the big city to find a position, but fails to do so. Oswald Trumble, so known to society, though in reality a master crook, strolls through the park, his mind busy with a scheme to steal the jewels of Mrs. Crosby Moore, a leader of society, whose forthcoming fancy-dress ball is the talk of the town. As Trumble approaches the bench where Jason is seated, the young man arises, shows exhaustion and then slowly continues on his way. Struck with Jason's clean-cut appearance, Trumble follows the young man, trails him to the river, and prevents him from committing suicide.