The shipyard worker accused of setting fire to the USS Miami can now waive indictment and plead guilty, or Assistant U.S. Attorney Darcie McElwee said she will present the case to a grand jury.

"There may be an indictment within 30 days if the grand jury returns one," McElwee, the lead attorney in the case, said Thursday.

Casey James Fury will be held in jail until his case is decided, a magistrate judge ruled at a detention hearing at U.S. District Court in Portland, Maine, Wednesday.

Fury, 24, of Portsmouth, N.H., was charged with two counts of arson for fires on and around the Groton-based submarine that caused an estimated $400 million in damages. The Miami was in a dry dock at the Portsmouth Naval Shipyard for maintenance and upgrades.

The Senate Committee on Appropriations approved the fiscal year 2013 defense bill Thursday, and it includes $150 million for repairs on the Miami. The submarine was built for $900 million and commissioned in 1990.

Fury, who worked at the naval shipyard as a painter and sandblaster, faces life in prison, a fine not to exceed $250,000 and restitution.

Wednesday's ruling on the motion for detention started the clock since the government now has 30 days to secure an indictment unless both sides agree to extend the deadline.

If indicted, Fury would be arraigned and a trial would be scheduled, which typically happens 70 days from the time of the indictment, McElwee said. If Fury waives indictment, a plea hearing would be held, followed by sentencing at least two months later.

"He'll be in jail for quite a while," she said.

McElwee said she could not comment on whether she is pursuing additional charges. Fury's public defender, David Beneman, said Thursday he could not talk about a pending case.

Fury is accused of setting a fire on board the Miami on May 23 that started at 5:41 p.m. and burned until 3:30 a.m. the next day, causing extensive damage to the forward section. He is also accused of starting a second, smaller fire in the cradle that held the Miami in the dry dock at about 7 p.m. June 16, and it was quickly extinguished.

According to the criminal complaint, Fury first admitted to investigators he lit alcohol wipes on fire on June 16 because he was anxious over texts he received from his ex-girlfriend and wanted to leave work. He later admitted to setting rags on fire to start the larger blaze, it said.

Fury, who told investigators he was taking medications for anxiety, depression and insomnia, checked himself into an in-patient mental health facility June 21 and checked out two days later, the complaint said. He went with investigators on board the USS Pasadena, a Los Angeles-class submarine similar to the Miami, and demonstrated how he set the May 23 fire, it said.

The Naval Criminal Investigative Service conducted the investigation with help from the Bureau of Alcohol, Tobacco, Firearms and Explosives.

j.mcdermott@theday.com