The federal government is investigating kosher slaughterhouses and suppliers for possible antitrust practices, according to a lawyer for one of the firms. AgriProcessors Inc., the world's largest kosher slaughterhouse, received a grand jury subpoena requesting documents and was cooperating with the investigation, attorney Nathan Lewin said Friday. "It has been told that neither the corporation, nor any corporate officer or employee is presently a target of the investigation," Lewin said in a statement. It was not immediately clear exactly how many slaughterhouses and suppliers were involved in the probe. Lewin said a number of meatpackers had received subpoenas. The US Department of Justice did not immediately return a phone call for comment from The Associated Press late Friday. A telephone number listed for AgriProcessors Inc. was out of service Saturday. The investigation was first reported Thursday in The Jewish Week newspaper. Based in Postville, Iowa, AgriProcessors employs about 700 people. Trained rabbis at the plant slaughter cows at a rate of about one every three minutes. The meat is sold under the brands Iowa's Best Beef, Rubashkin's and Aaron's Best. The slaughterhouse became the focus of controversy two years ago when People for the Ethical Treatment of Animals, or PETA, made public an undercover videotape showing steers walking or bellowing up to three minutes after their throats were slit. The group claimed the video proved the animals were conscious and victims of cruel and inhumane treatment. Company officials have said that PETA's claims were misguided and that the video depicted only the involuntary movements animals make after death.