MADISON, Wis. -

The state Department of Justice has begun investigating an agent who claims his boss in the Division of Criminal Investigation was selling weapons illegally.

DCI agent Dan Bethards had accused the former head of the state DCI's Superior field office of selling guns without a federal license.

In a letter dated Monday, DCI Administrator Dave Matthews told Bethards he was being placed on paid administrative leave while he was being investigated for possible policy violations.

Three days later Bethards filed a whistleblower complaint.

The DOJ says it's "concerned about the motivations of Mr. Bethards" and that it didn't expect the boss to be charged.

The Bureau of Alcohol, Tobacco, Firearms and Explosives says individual private weapons transactions are common, and selling without a license typically doesn't rise to a federal violation.