Proponents of a Northern Virginia transportation tax criticized opponent groups yesterday for using a cartoon of an armed bandit in a mass mailing and for borrowing telephones at the Fairfax County headquarters of Gun Owners of America Inc. to mobilize voters in the Nov. 5 sales tax referendum.

Mary A. "Mame" Reiley, chief political strategist for the pro-tax side, said the cartoon and the use of the donated space and telephones at the Gun Owners were "extremely insensitive" in view of the sniper attacks that have put the region on alert since early October.

"Everybody's on edge, and rightly so, and these are not the political tricks you use," said Reiley, of Citizens for Better Transportation. "It's very disturbing, at a time like this."

The cowboy caricature and the use of the Gun Owners space in Springfield were arranged separately by two groups fighting the proposed regional increase in the state sales tax rate. On Nov. 5, voters in nine Northern Virginia jurisdictions will decide whether to increase the rate from 4.5 percent to 5 percent on sales of most goods.

The sales tax revenue, estimated to be $5 billion over 20 years, would be earmarked for highway and mass transit programs.

Spokesmen for the environmental groups that are fighting the sales tax proposal said the bandit cartoon on the group's brochure was meant to illustrate their contention that the sales tax revenue constituted "highway robbery," underwriting sprawl and more gridlock across the region. The scowling cartoon bandit holds a revolver in one hand and a bag of money in the other.

Christopher G. Miller, president of the Piedmont Environmental Council, which mailed the brochure to 50,000 homes at a cost of $17,200, said, "Unfortunately, the timing is terrible, and we acknowledge that and apologize for it."

Stewart Schwartz, executive director of the Coalition for Smarter Growth, which supported the mailing, said the brochure was mailed late last week but was produced before the sniper attacks began Oct. 2.

"This whole thing was out of sight, out of mind," said Schwartz, adding that he had fielded one complaint about the cartoon, which was superimposed on an image of a typical Washington area traffic tie-up.

"I can't tell you how upset I was yesterday that there was some sense of hurt over that," Schwartz said.

James T. Parmelee, a spokesman for the anti-tax coalition that is also battling the referendum, said his group of tax opponents appreciated the use of about a dozen phones at the Gun Owners office to contact voters and prospective volunteers.

"We don't have the money the other side does, and people are volunteering their places of business for phone banks," Parmelee said. "A number of groups -- anti-tax, pro-Second Amendment, environmentalists -- are pitching in, and we welcome help from everybody."

"I don't think it connects to what's going on with the whole sniper thing at all," Parmelee said.

Although the tiff between the two sides of the sales tax referendum played out yesterday on the margins of the larger debate, both camps agreed that it reflected the heightened sensitivities of a jittery region that will go to the polls in less than two weeks.

The discussion also confirmed the enormous political stakes on Nov. 5, as each side struggles for even the slightest political advantage in a closely fought election where voter turnout may be skewed by fears of the sniper.

Schwartz said the bandit cartoon was "meant to capture the sense of what we thought of the referendum. Certainly, we share everyone's grief and anger over the sniper, and no connection was ever intended or implied."

However, J. Randall Minchew, a Leesburg lawyer and vice chairman of the Loudoun County Republican Committee, said he was "amazed" that the environmental groups "would stoop to using symbols of the D.C. area sniper to push their agenda and stir up fear amongst the electorate."

"Their insensitivity is remarkable," Minchew said.

Stewart Schwartz said the anti-tax flier was prepared before the sniper attacks began but was mailed later.