The top federal prosecutor in Alaska confirmed Friday that a criminal investigation is underway concerning an alleged scheme to confuse voters by placing a Senate candidate on the ballot with the same name as the Republican incumbent.

U.S. Attorney Michael Heyman stated that the investigation, ongoing for several months, has seen a "significant surge of law enforcement assets to Alaska" following revelations this week that Democratic Senate candidate Mary Peltola’s campaign may have been involved in recruiting Dan J. Sullivan Jr. to run.

"When credible information comes out, we are committed to pursuing that information to deceive voters and we will act on it. We are acting on it intensely and swiftly," Heyman told reporters. He declined to specify potential crimes or targets of the probe but urged the public to provide tips.

Peltola has denied any knowledge of the effort to place Dan J. Sullivan Jr. on the ballot, where she is challenging Republican Sen. Daniel Sullivan. "I just want to clear the air," she said Thursday. "I knew nothing about any other candidate on the ballot except for me and the incumbent. That is all I have ever known about. I am not interested in tricking voters."

Federal prosecutors have issued dozens of grand jury subpoenas and requests to preserve records, according to a person familiar with the matter. Dan J. Sullivan has consistently denied running at the behest of Democrats and has stated he had no contact with Peltola’s campaign.

The Alaska Senate race is among several contests this year expected to influence control of the U.S. Senate.