Congress's investigation into IRS political targeting accelerated Wednesday, with a referral for the criminal prosecution of a former Treasury official and new evidence to back it up. In a letter to Attorney General Eric Holder, House Ways and Means Chairman Dave Camp recommends the Justice Department proceed on three probable criminal actions taken by former director of Exempt Organizations Lois Lerner.

The letter, which was endorsed in a party-line Ways and Means vote Wednesday morning, discloses new evidence suggesting that...