Jessie L. Bonner, Associated Press
Idaho Treasurer Ron Crane is shown in his office at the state Capitol in Boise, Idaho, Tuesday Nov. 8, 2011.

BOISE — A southwestern Idaho prosecutor is scrutinizing whether state Treasurer Ron Crane broke the law by using a state credit card to fuel up a personal vehicle he drives to and from the Capitol, and on short excursions to grocery stores or church.

Canyon County prosecutor Bryan Taylor confirmed that Idaho Legislative Services auditors who have been reviewing the financial records of Crane's office for months have forwarded their preliminary findings to him.

"They've asked us to see if any criminal offense took place within Canyon County's jurisdiction," Taylor said. "We're fairly early into that investigation."

Legislative Service audits division manager Don Berg declined comment, saying he's awaiting Taylor's conclusions before releasing the audit of Crane's office. The audit is conducted at least once every three years, by state law.

Crane claims he's saving the state money by using a personal car. However, he doesn't keep a detailed record or logbook to show everywhere he drove using gas paid for by taxpayers.

Crane has hired attorney David Leroy, a former Idaho attorney general, to represent him after auditors alerted current Attorney General Lawrence Wasden's office about concerns that Crane's activities may have broken the law.

"As a former prosecutor, I can state that these kinds of policy and practice review questions are occasionally presented to public council for review," Leroy said Tuesday. "I would anticipate that the Canyon County prosecutor will conclude this involves questions of public policy and that no finding of criminal conduct will be made."

Leroy contends that Crane — as an elected official and not just a state employee — has the discretion to make decisions about the most-efficient and cost-effective means of organizing his official travel.

According to Idaho government policy, use of state vehicles for personal business is strictly prohibited. While personal vehicles may be used for official business in some situations, state policy indicates the cost of travel should be reimbursed at a state-approved rate — currently 45.5 cents per mile — with the mileage computed according to approved state or national maps.

Crane didn't turn in mileage reimbursements, instead using his state card to buy fuel.

The bill for Crane's state Chevron card over the last three years totaled about $6,900, according to documents obtained through a public records request.

The bill was about $2,030 in 2009, $2,875 in 2010 and $1,980 for the first nine months of 2011.

In a recent interview with The Associated Press, Crane said he's used a state Chevron card with a $1,500 spending limit to fill up his own car since February 2005, when he gave up a state-provided vehicle in a bid to save Idaho taxpayers money.

Crane said he only uses gasoline paid for by Idaho taxpayers for commuting to the Capitol, as well as for other official business. Personal travel, he said, is paid out of his own pocketbook.