AUGUSTA (AP) — A Republican hoping to unseat U.S. Sen. Angus King is facing challenges about the veracity of his signatures he collected to qualify for the June primary.

Maine Secretary of State Matt Dunlap says the state will hold a public hearing Thursday on the challenge against financial planner Max Linn filed by opponent Republican Sen. Eric Brakey.

Brakey claims Linn filed signatures of dead voters and hundreds of duplicates. Linn has called Brakey’s complaint a “prank.”

Dunlap has already verified Linn’s signatures.

Dunlap said he’ll preside over the hearings and decide whether to disqualify Linn. A challenger or candidate can appeal such a decision with a legal action.

The two Republicans hope to face off in their party’s June primary in an attempt to unseat King, an independent.

Republican U.S. Senate candidate Max Linn, in a photo from his campaign’s Facebook page.