Seattle area fire authorities continue to investigate a multi-alarm fire that broke out late July 4 night.

The Lake Union Skylaunch Marina is home to about 250 boats, and 14 of them were destroyed in the blaze.

Officials say the blaze was reported shortly after 10pm Thursday night.  They believe illegal fireworks launched from a nearby hill were the cause.  One of them reportedly landed on a boat, touching of a fire that was hard to put out.

Witnesses said as soon as firefighters thought they had it extinguished, it came jumping back. One firefighter was treated for minor injuries.

Authorities did not specify if those found responsible will face charges, but it is likely.  Marina officials say it was lucky the fire did not destroy more boats, or reach any fuel storage areas.