The FBI's crime statistics are the official yardstick of just how much evil lurks in the hearts of men. The arithmetic does not reflect favorably on the FBI, which seems powerless to cope with the rising crime rate.

The G-men nevertheless show no embarrassment over the increase. The more crime that is committed, the more money they require to fight it. So at appropriations time, they point to the grim statistics not as evidence of their own inadequacy but as justification for a bigger budget.

Usually, Congress is duly impressed and votes the FBI the funds it requests to safeguard the nation. Yet the Justice Department's internal documents show this money is sometimes misspent.

Here are some of the improprieties documented in records that the public was never supposed to see:

"Emergency purchases," which do not reequire contracts or even purchase orders, have been used by G-men to avoid regular accounting channels. These supposed emergencies result in expenditures of millions of dollars each year, and have included payments for agents' physical exams, auto repairs, conference expenses, laundry, ;office supplies, parking, tuition and utility charges.

The bulk of FBI contracts were found to have gone to "sole source" suppliers: noncompetitive awards that are an open invitation to sweetheart arrangements. The investigators found cases in which contractors submitted unsolicited proposals and then coached bureau officials on ways to justify contract awards without competitive bidding.

A 1976 internal investigation found that FBI officials had been guests of the Remington Arms Co. at a weekend hunting retreat a few years earlier. The company paid for accomodations, hunting licenses, liquor, ammunition and guides. The investigation concluded that it was all right, however, because Remington had no FBI contracts at the time. But documents show that the bureau was buying thousands of dollars' worth of Remington shotguns under small-purchase procedures.

The bureau recently bought new office furniture, though it had $279,000 worth of furniture in storage -- in a warehouse that costs $16,909 a year.

When the Marriott Corp.'s food service contract for the FBI Academy at Quantico, Va., came up for renewal some years ago, an FBI official recommended soliciting competitive bids only to "keep within the sphere of federal . . . regulations." The time for submitting bids was so "unduly restrictive," the auditors concluded, that only one competitor made the deadline. The result was succinctly summarized by the routing slip of the review committee: "Memo with our recommendation on way up! Of course it is Marriott." In 1976, Marriott offered $15,000 to lthe FBI recreation association's snack bar. Marriott says it was not a donation, but was "intended as our own investment to upgrade the existing facility." The FBI's legal counsel shot down the proposal.

About 1,000 revolvers were purchased solely from Smith & Wesson on grounds that non-uniformity of handguns would create a safety hazard. FBI officials also said the S&W revolver was the only weapon used in most of its gun battles. But government auditors found that agents are in fact allowed to carry Smith & Wessons or Colts, according to preference.

In the absence of documentation, auditors were unable to determine whether the FBI had actually received many of the goods and services which invoices showed had been paid for.

Footnote: One member of Congress is not willing to give the FBI a blank check. He is Sen. Orrin G. Hatch (R-Utah), whose investigators are checking on FBI expenditures. He's planning to take up the matter with FBI Director William H. Webster.