On an overcast Friday morning last January, longshoremen all over New York Harbor walked off the docks, bringing the port nearly to a stop for a day. What were the longshoremen’s grievances? What were their demands? Many of the men seemed not to know. They hung around the food trucks and milled about the parking lots, unsure why they had stopped working and unsure what it would take for work to resume.

“No one knew what that was about,” one recalled recently.

A year later, the reason for the strike remains unclear, even as the agency tasked with ridding the waterfront of organized crime, the Waterfront Commission, has questioned dozens of longshoremen under oath. One told the commission he learned of the strike early that morning, when it was too dark to see the face of the man giving the order. It could have been anyone.

It was the old D & D — Deaf and Dumb, the classic longshoreman’s response, popularized in the 1954 film “On the Waterfront.”

In that movie, the longshoremen were reluctant, even frightened, to talk to the authorities, whether a priest or a detective, because the mob controlled the waterfront. In the years since, much has changed around New York Harbor; the heavy lifting is done not by hand but by cranes, and human voices are scarcely heard amid the beeping of the straddle carriers, giant insectlike machines that move containers back and forth. But even as New York and New Jersey’s increasingly valuable shoreline is claimed by luxury development, investigators say the mob is still present.