AUGUSTA — A businessman who considered challenging Mike Michaud in the Democratic gubernatorial primary says the party breached a written agreement and conspired against him in a state Senate primary that he lost.

In his complaint, Steve Woods of Yarmouth alleged that the conspiracy involved party leaders who promised to stay neutral in his June 10 primary contest against Cathy Breen of Falmouth.

The agency that enforces Maine campaign laws voted Wednesday to investigate whether the Falmouth Democratic Town Committee should have registered as a political action committee in communicating its endorsement of Breen before the primary.

Woods said he might not have dropped out of the gubernatorial contest if party officials hadn’t agreed to remain neutral in his bid for a state Senate seat.