SACRAMENTO, Calif.—A former legislative leader violated state law when he used campaign money to purchase a state vehicle and have it titled under his name, California's campaign watchdog said Monday.

The Fair Political Practices Commission issued a warning letter to former Senate minority leader Bob Dutton but did not impose a fine.

Dutton, a Rancho Cucamonga Republican, used campaign money to buy the 2005 Chevrolet Tahoe, which had been his state-issued vehicle.

Gary Winuk, chief of the commission's enforcement division, said in the letter made public Monday that Dutton violated campaign law because the vehicle's title was in Dutton's name individually as well as in the name of his campaign committee.

Winuk said the commission decided against a fine because Dutton told investigators he used his name to obtain insurance. He has since sold the vehicle and returned the money to his campaign account.

The commission's inquiry was based on an examination by The Associated Press, published last month, that focused on at least a dozen lawmakers who had their vehicles repaired at taxpayers' expense in the final weeks before they bought them for personal use. Dutton's vehicle had nearly $6,000 worth of repairs, including a dent repair and a detailed cleaning, shortly before he bought it as the Legislature's vehicle program ended in late 2011.

The AP's investigation found 64 lawmakers had repairs made at state expense in the nine months before the program ended. Of those, 37 bought their vehicles.

Dutton was the only lawmaker to use campaign money to buy his previously state-provided vehicle. He ran unsuccessfully for Congress last year as he was termed out of the Legislature.

"It wasn't like I went out and bought a Mercedes or anything like that," Dutton said Monday.

He said he would not contest the warning letter.

"It was a technical violation," Dutton said. "If I'd left my name off it, it would have been fine."