Details were found in an Office of Congressional Ethics report, which concluded the trip appears to have been "for personal purposes."
An August report says there is "substantial reason to believe" that Marlin Stutzman used campaign funds to pay for a personal family trip to California.
Stutzman came under criticism during the primary after The Associated Press reported that he billed his campaign more than $2,000 in airfare for a family trip.
For some Stutzman loyalists, throwing their support behind Todd Young won’t be easy.
The current 9th District Indiana congressman moves on to face former 9th District Rep. Baron Hill.
Republican Reps. Marlin Stutzman and Todd Young are competing for the GOP spot on the November ballot.
FEC regulations forbid the use of campaign funds for personal expenses.
Political analysts question whether the debate will change the minds of undecided voters.
The commission voted two to two, meaning Young will remain on the ballot. Its ruling can be appealed in court.
Democrats claim Young doesn’t have the required number of signatures to be on the ballot and Stutzman is joining the challenge.