LOS ANGELES (AP) – Federal investigators identified a violation of Coast Guard regulations that could trigger criminal charges in the California dive boat disaster that killed 34 people.

The National Transportation Safety Board said Thursday that all crew members on the boat Conception were asleep when the pre-dawn fire broke out Sept. 2 off the coast of Santa Barbara.

The boat was required to have a crew member on roving patrol while passengers slept, according to Coast Guard rules and the boat’s inspection certificate.

Experts say not having a lookout could be enough to bring criminal charges under the obscure so-called seaman’s manslaughter statute.

The 19th century law carries penalties up to 10 years in prison if a captain or crew were negligent or committed misconduct or neglected their duties.