It has been five years, but the memory still haunts construction superintendent Michelle Brown.

A co-worker ended his workday by giving away his personal cache of hand tools to his colleagues. It was a generous but odd gesture; no one intending to return to work would do such a thing. The man went home and killed himself. He was found shortly afterward by co-workers who belatedly realized the significance of his gifts.

"It's a huge sign, but we didn't know that then," Brown says. "We know it now." Read more...