The fire that preceded the sinking of the Deep Sea crab boat in Penn Cove last spring has been determined to be the result of arson, according to a report released by the state Department of Natural Resources today.

The investigation, conducted by the King County Sheriff’s Office’s fire/arson investigation unit, determined that an unknown number of people “ignited and burned” the vessel prior to it’s sinking, May 12.

The blaze is believed to have started in the vessel’s freezer hold, which was located on the forward deck, but what was used to start the fire could not be determined, said Craig Muller, supervisor for the special fire unit.

“It was an undetermined source of ignition,” Muller said.

Also, no suspects have been identified and Toni Weyman Droscher, a DNR spokesperson, confirmed that the agency will not be pursing the matter further.

“It’s pretty much a closed case,” she said.

The Deep Sea arrived in Penn Cove by tow in December of 2011. The vessel sat at anchor just outside Penn Cove Shellfish’s mussel rafts for the next four months until it caught fire and sank.

The vessel spent three weeks on the bottom, spilling more than 5,000 gallons of diesel fuel into Penn Cove, before it was raised and towed to Stabbert Yacht and Ship dry dock in Seattle.

The fiasco resulted in local closures of shellfish harvesting and cost state and federal agencies about $3 million.

Although DNR will not spend more resources trying to find out who started the fire, both it and the state Department of Ecology are attempting to recover expenses from the vessel’s owner, Rory Westmoreland.