Gasoline prices continue to fall across the nation and are even starting to drop in Utah, but not fast enough, according to Francine Giani, executive director of the Utah Department of Commerce.

On Monday, Utah's gasoline prices averaged $2.80 for a gallon of self-serve regular, ranking the fourth highest in the nation, according to AAA's Fuel Gauge report. A month ago, Utahns were paying an average of $2.99 a gallon.

Only Alaska, Hawaii and Nevada have higher gasoline prices than Utah.

Nationally, the average price of a gallon of self-serve regular gasoline on Monday was $2.38, a decrease of 50 cents, or 17 percent, over the past month.

"I can't figure it out," Giani said. "What we're telling people to do is hunt down those places that can give you the best price available. If you've got to go a mile to get a little cheaper gas, I would do that."

Giani is leading an investigation launched Sept. 15 by Gov. Jon Huntsman Jr. into Utah's high gasoline prices. On Monday, Giani sent a letter to the Utah Petroleum Association asking for further information related to the investigation.

Specifically, Giani wants to know the source of oil purchased by Utah's five refineries — whether it is domestic crude, Canadian crude or international crude. Giani also is asking for the daily price per barrel paid by the refineries for crude oil for each day from Oct. 1, 2005, to the present.

In addition, Giani is asking for the percentage of profits from the sale to retailers of all grades of unleaded gasoline that has been used by the refineries to subsidize the transition to ultra-low-sulfur diesel fuel.

Calls to the Utah Petroleum Association by the Deseret Morning News seeking comment were not returned by deadline Monday.

"We've got tons of questions, and they beg an explanation," Giani said. "We're just trying to get to the bottom of it. Will there be a violation of the law? I don't know."

Giani said two state statutes — the Unfair Practices Act and the Consumer Sales Practices Act — would likely be a stretch to apply to charging individual retailers. Federal antitrust laws would carry a bigger punch, but collusion between retailers and/or oil refineries would set a high burden of proof.

In the meantime, Utah consumers appear to be outraged over the state's continued high gasoline prices.

"As a former prosecutor, I'd be glad to prosecute these bloodsuckers for free when the evidence is established by investigators," said Mark Kleinfield in an e-mail to the Deseret Morning News. "Crooks in suits are still crooks."