I started watching flight radar on Thursday after I kept hearing helicopters land at Maine med, and while I was poking around on flight radar, I saw some interesting planes in the search for Card. 

It seems to indicate that they really thought he escaped down the river. That may be a bit obvious at this point, but the lack of information at the time didn’t feel as obvious.
WGME also confirmed the USCG was supporting by air and sea late Thursday, but it wasn’t a helicopter as used in the photos.

N714JQ - Is a Maine Marine Patrol Aircraft. Looks like it ran a route from Lewiston down the Androscoggin to the sea. Then later, all the way up to Augusta. During that flight they were at only 800 feet which is very low, clearly searching for him.

C2304 - Is a USCG Airbus HC-144 Ocean Sentry aircraft. Seems to have been searching the same river and ocean inlets on the coast.

Of note from the Wikipedia article on it: it was chosen for its “better performance in the low-level observation role.” “It also “uses electronic systems on the Mission System Pallet roll-on, roll-off electronics suite from Lockheed Martin” so they probably had their best cameras and sensors aboard.

FORGE53 - This one is a real wild card. They flew up from Joint Base Andrews in Washington, DC to Brunswick Executive on Friday as the search was dragging on. There were a few other flights to Portsmouth International / Pease in its flight history, but that would make a bit more sense because it is an army plane. Going direct to Brunswick seems to indicate that they were going there to drop people off to directly assist with the search.

Hope it helps make some sense of this tragedy and the bickering that’s now happening with state law enforcement.

Interesting Planes in the Search for Lewiston Shooter