FBI agents frequently violate the bureau's rules for handling confidential informants, instructions that were rewritten following FBI abuses in the 1990s, the Justice Department's internal watchdog said Monday.

A review of 120 confidential informant files from FBI offices around the nation found violations in 104 cases, or 87 percent, Inspector General Glenn A. Fine said in a 301-page, partially blacked-out report that examined the FBI's compliance with rules that govern most investigations.

Agents failed to assess informants' suitability, get authorization for informants to engage in activity that otherwise would be illegal, convey proper instructions or tell prosecutors when informants had committed serious crimes, Fine said.

Update: The link to the OIG report is here. Last Night in Little Rock quoted on this in Boston.com (Boston Globe)