Judging by the mail flowing into offices of members of the Iran-contra investigating committees, the American people haven't yet determined the heroes and villains of the affair.

They do, however, offer opinions about the committees' work. Take this telegram from a Key Largo, Fla., man: "The more hearings I view, the more I am convinced of the monumental stupidity of the individual members of the Congress of the United States."

And this from a Burbank, Calif., man: "Keep up the excellent work."

The authors are among those who have taken time to drop a line to Sen. Daniel K. Inouye (D-Hawaii), chairman of the Senate select committee, since the panel's televised daytime drama began seven weeks ago.

Inouye's committee has received about 6,000 letters. Across the Capitol, House select committee staff members say they have received between 200 and 300. Offices of individual committee members report a steady flow of letters about the Iran investigation, but not a flood.

Congressional staffers who have sifted through the piles of letters say the mail offers widely mixed reviews of the committees' performance.

While some correspondents accuse the committees of persecuting patriots, wallowing in trivialities and exploiting their platform, others praise the panels for honorably discharging a solemn duty.

"It seems the panel fantasizes that a huge halo hovers over its collective head," a Tampa, Fla., woman says in a letter to Rep. Henry J. Hyde (R-Ill.), one of the administration's strong supporters on the panel. "Actually the members are displaying to the concerned public their selfish political grandstanding."

A man from Foster City, Calif., complains to Sen. Orrin G. Hatch (R-Utah) that the hearings are distracting the country from an urgent communist threat in Central America. "It reminds me of being hassled for an hour by a motorcycle cop over whether you were speeding when you are trying to reach the home of a friend or loved one whose home is burning around them," he says.

On the other side of the issue, a Baltimore woman commends the committees for their courage. "It takes a brave person to call a halt to neo-McCarthyism, to blatant disinformation, to 'patriotic' zealotry," she says. "The persons who can muster this courage will be the true patriots, the true heroes of this terrible tragedy."

Other correspondents fault the panels on a different score, complaining that they have not been determined enough in pursuing the truth.

"Why, oh why, is {the panel} permitting Republicans (and witnesses) the use of this PUBLIC hearing for repeated flag-wrapped speeches in defense of a faulted, frenzied foreign policy?" a Chevy Chase woman asks in a letter to Inouye. "This is NOT a foreign policy hearing, yet this one-sided foreign policy discussion is permitted its intrusion again and again and again."

In addition to the mail, committee members' phones have been ringing with calls from people watching the hearings on television. The "C-SPAN people," as one congressional aide describes viewers, call in to offer suggestions and a running commentary on the line of questioning.

Then there are letters that add a new dimension to the drama, like the one from a Bakersfield, Calif., man who asked the inquisitors for protection. "Would you please make law to prohibit Dinosaur spy from China and Taiwan come to U.S.A. and persecute me," the correspondent writes.

The letter was addressed to "Senators, Subversive Committee, Congress of the U.S." It was delivered to the select committee.

Most committee members would not permit reporters to read their mail, but three of those contacted did. The Senate committee provided 11 letters that a staff member described as a representative sample. The letters were provided on the condition that the authors not be named.

While some ranking members of the panels have collected more than 1,500 pieces of mail since the hearings began May 5, others have received a mere trickle. None of the legislators report that the scandal is dominating their mail.

Rep. Edward P. Boland (D-Mass.), who sponsored the amendment that temporarily outlawed U.S. aid to the Nicaraguan rebels, has received 25 letters about the Iran affair, according to a spokesman.

H.D. Palmer, a spokesman for Sen. James A. McClure (R-Idaho), says that only 2 percent of the 3,000 letters McClure received from constituents during the first six weeks of the hearings concern the investigation, although McClure also received Iran letters from around the country.

"The primary fixation of people in the state is not the hearings," he said, adding that Idaho voters are more interested in commodity credits, trade legislation and forest management.

In the office of Rep. Dante B. Fascell (D-Fla.), press aide Barbara D. Burris says the mail has been lighter than expected. "I don't know whether people just aren't interested or they're not watching the hearings or they're overwhelmed by the detail," she said.

Fascell's 250 letters on Iran hardly compare to the thousands he received when a massive boatlift inundated southern Florida with Cuban refugees, or to the mountains of mail sent to his office during the Watergate hearings, Burris said.

As the Senate committee struggles to reply to each of its correspondents, letters are accumulating unread at the House committee's office.

"We've made no attempt to catalog them," said committee spokesman Robert Havel. "We don't have the space, the time or the staff to go through it all."