LOS ANGELES (AP) — Prosecutors are seeking restitution for the families of 34 people killed in a scuba dive boat fire in 2019 that was the deadliest maritime disaster in recent U.S. history.

A judge will determine the amount on Thursday during a hearing in federal court in Los Angeles. The proceeding comes nearly five years after the Sept. 2, 2019, tragedy off the central California coast, which prompted changes to maritime regulations, congressional reform and several ongoing civil lawsuits.

The captain of the Conception, Jerry Boylan, was convicted last year of one count of misconduct or neglect of ship officer following a 10-day trial in federal court in downtown Los Angeles. The charge is a pre-Civil War statute colloquially known as seaman’s manslaughter that was designed to hold steamboat captains and crew responsible for maritime disasters.

He was sentenced to four years in prison and three years of supervised release. He is out on bond and must report to the Bureau of Prisons by Aug. 8. His appeal is ongoing.

The Conception was anchored off Santa Cruz Island, 25 miles (40 kilometers) south of Santa Barbara, when it caught fire before dawn on the final day of a three-day excursion, sinking less than 100 feet (30 meters) from shore.

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Thirty-three passengers and a crew member perished, trapped in a bunkroom below deck. Among the dead were the deckhand, who had landed her dream job; an environmental scientist who did research in Antarctica; a globe-trotting couple; a Singaporean data scientist; and a family of three sisters, their father and his wife.

Boylan was the first to abandon ship and jump overboard. Four crew members who joined him also survived.

Although the exact cause of the blaze remains undetermined, prosecutors blamed Boylan for failing to post the required roving night watch and never properly trained his crew in firefighting. The lack of the roving watch meant the fire was able to spread undetected across the 75-foot (23-meter) boat.

But Boylan’s federal public defenders sought to pin blame on boat owner Glen Fritzler, who with his wife owns Truth Aquatics Inc., which operated the Conception and two other scuba dive boats, often around the Channel Islands.

They argued that Fritzler was responsible for failing to train the crew in firefighting and other safety measures, as well as creating a lax seafaring culture they called “the Fritzler way,” in which no captain who worked for him posted a roving watch.

The Fritzlers have not spoken publicly about the tragedy since an interview with a local TV station a few days after the fire. Their attorneys have never responded to requests for comment from The Associated Press.

Three days after the fire, Truth Aquatics filed suit under a pre-Civil War provision of maritime law that allows it to limit its liability to the value of the remains of the boat, which was a total loss. The time-tested legal maneuver has been successfully employed by the owners of the Titanic and other vessels and requires the Fritzlers to show they were not at fault.

That case is pending, as well as others filed by victims’ families against the Coast Guard for what they allege was lax enforcement of the roving watch requirement.