A text message between two FBI employees from September 2016 released by a Republican senator Wednesday says that then-President Barack Obama “wants to know everything we’re doing.”

What exactly the text refers to isn’t specified in the exchange. Associates of the FBI employees said it refers to preparation to brief Mr. Obama about Russian interference in that year’s election. Sen. Ron Johnson (R., Wis.), who released the text Wednesday as part of a 25-page report, said it raises questions about meddling by Mr. Obama in the...