Who led the attack on Essex in 1814?

Early in the morning on April 8, 1814, British marines from the blockade squadron in Long Island Sound, entered the Connecticut River on six barges to "fire" American shipping. Finding Saybrook Fort unmanned, they proceeded to Essex. They occupied the town for some six hours and burned some twenty-three vessels.
The ship, the Osage, was still on the stocks at a yard in North Cove when the British struck. In an attempt to save her, the blocks were knocked away and she was prematurely launched, but she finally burned to the water line. The British then escaped down river.

The losses incurred at Essex harbor amounted to some $200,000 (a substantial sum in those days).

Information courtesy of the : Connecticut River Museum. More information is available on the Raid at Essex.