Federal transportation security officials and a private security company at San Francisco International Airport cheated on undercover tests of screeners at passenger checkpoints, the US Department of Homeland Security has found. The department's Office of Inspector General concluded workers with the Transportation Security Administration and Covenant Aviation Security compromised nearly a year's worth of tests by using surveillance cameras to track undercover agents as they made their way through the airport. Security officials would notify screeners as the agents approached checkpoints, radioing in their physical descriptions and sometimes even the agents' methods for concealing contraband, the department said in a report released Thursday. The department found tests were undermined from August 2003 to May 2004 - a period during which officials at the airport were trying to demonstrate that Covenant screeners were as good as or better than TSA screeners. Covenant officials did not immediately return a message Friday night. San Francisco was the only major airport in the country chosen in 2002 to be part of a pilot program using private security screeners instead of TSA employees. The TSA last month awarded Covenant a four-year contract worth more than $300 million to continue screening at the airport. "We have confidence in their ability to do their job and think they are doing a good job," Melendez said. The investigation began in 2004 after a Covenant screener balked at giving screeners descriptions of undercover agents, then wrote a letter to the TSA detailing the practice. The TSA asked the inspector general's office to investigate after it received the whistle-blower's letter. TSA spokesman Nico Melendez said the agency disciplined some employees but considers the matter closed.