Suspected Boston Marathon bomber Dzhokhar Tsarnaev was unarmed when he took shelter in dry-docked boat and surrendered to authorities, investigators said.

No gun was found in the boat where cops busted Tsarnaev, 19, following a massive manhunt that virtually shut down all of Boston on Friday.

Tsarnaev had been hiding in a boat stored in the backyard of a Watertown, Mass., home. Officers fired a hail of bullets toward the boat before Tsarnaev complied with an FBI negotiator and gave up.

But investigators now say that no firearm was found in the craft.

When Tsarnaev was taken into custody, he had wounds to the neck, leg and hand, officials said.

The neck was believed to be a self-inflicted wound and botched suicide attempt, authorities said shortly after his arrest.

The boat’s owner had been stuck inside all day, observing a stay-at-home order by Gov. Deval Patrick. The homeowner saw blood near the boat and found Tsarnaev hiding inside.

The man called authorities before helicopters, using sophisticated infrared cameras, confirmed someone was hiding in the boat.