AG rival has spent more than reported

Yet in an interview with the Associated Press, McKenna estimated he spent $5,000 on his race — more than triple what was reported. The first-time candidate also did not account for the linchpin of his campaign — the production of 100,000 stickers printed with his write-in information — and appears to have paid that expense illegally.

“That was something which I put on my personal credit card,’’ McKenna, 49, said. “There should be a record. That was essentially a loan from me to the campaign.’’

Last month, the state Office of Campaign and Political Finance fined Christy Mihos, a former Republican gubernatorial candidate, $70,000 for using personal and business funds to pay more than $112,000 in expenses incurred during his unsuccessful 2010 campaign.

Candidates for statewide office must use a campaign checking account for expenses, which the bank then discloses on the state’s campaign finance website, said Jason Tait, agency spokesman.

Laura Rigas, McKenna spokeswoman, said the candidate will file amended reports. “Jim has taken immediate action to rectify the easily correctable filing error upon learning of it,’’ Rigas added in a statement.

In the interview, McKenna also acknowledged a series of additional expenses that do not comport with the filings made in his bid to become the state’s chief law enforcement officer.

McKenna, a graduate of Boston College Law School who has worked in prosecutor offices in New Hampshire, Ohio, and Suffolk and Worcester counties, said in the interview that he succeeded in his campaign by traveling the state, speaking to the public, and, in some cases, steering them to his campaign website. Besides distributing the 100,000 stickers, he said, he mailed 16,000 postcards and 1,300 letters and “did some automated phone calling.’’

His reports show no expenditures for his campaign website, his Internet addresses, any electronic service providers, campaign meals, or travel.

McKenna’s reports also do not show any expenses for automated calls. In total, they show just $1,582.92 in expenses, including $42 in check-printing costs, $42.50 to a party planner, and $525.62 to his campaign manager for unspecified expenses.

Tait said some liabilities can exist for up to a year without being reported, but the aim of the campaign finance law is to reveal donors and expenses as they are incurred so the public can examine them.

Secretary of State William F. Galvin accentuated the scope of McKenna’s achievement yesterday. In releasing the state’s official primary results, he said McKenna garnered 27,711 write-in votes. He needed 10,000 to qualify for the general election ballot.

Galvin labeled it a “remarkable feat’’ and said he does not believe any write-in candidate has ever garnered that many votes.