Seagrave Holmes

 is a merchant in Rivet City who runs Rivet City Supply in the Marketplace. He deals in random junk and weapons.

Bannon, the owner of Potomac Attire, believes that Seagraves is trying to take over his seat in the city council, and asks you to find incriminating evidence, which can be found in Seagraves' Room.

However, should you decide to confront Seagraves with it, you can use it to remove Bannon from the council and install Seagraves as a council member.

If you are working on the Wasteland Guide quest, he is one of the persons to talk to in finding out the History of Rivet City

Apperances
 only appears in Fallout 3.