Tenpenny hired a team of wastelanders consiting of Mr. Crowley, dave, ted strayer's ancestor, and apparently others. They were sent to fort constantine by Mr. Tenpenny, though we don't know why.
Tenpenny says that he hired them to get some equipment for him. I think the power armor is unlikely to be the equipment in question as if they had failed to get it then there would have been no need to doublecross Crowley.
The Wiki claims that he was after a rare gun. I am not sure what all the dialogue choices lead to, but I seem to remember someone said something about a weapon. This could be a gun or it could be the Fusion pulse charge. The FPC seems more likely as Tenpenny does not have a rare gun.