The Justice Department has escalated its investigation over an Alaska Senate candidate who shares a name with the Republican incumbent, issuing a letter to a prominent Democratic attorney in Washington and others that they may be targets of the criminal inquiry, two people familiar with the matter said Tuesday.

The target letter to attorney Marc Elias, who for years has represented Democratic campaigns as well as the party itself in election-related challenges, is one of multiple such letters that were issued, said the people, who spoke on condition of anonymity to discuss an ongoing investigation.

They mark an overt widening of the investigation into potential voter confusion in the state.