A D.C. police official has asked that seven officers who may have been involved in a botched investigation of an attack on a cabdriver submit to lie detector or voice analysis tests.

Assistant Chief William P. McManus asked 3rd District officers to take the tests after learning that the cabdriver was allegedly turned away and treated rudely by police this month when he tried to return a knife left in his cab after the Nov. 16 attack.

Police and crime experts called McManus's request unusual, and union officials said they are concerned about what they called "drastic and unfair tactics against police."

McManus said the officers were told the tests were voluntary. But Sgt. Elania Byrd said: "They told me several times that if I didn't do it, I would be told to leave the police department. So I did it . . . I had an anxiety attack. I just left. Now I am on stress leave."

Executive Assistant Chief Terrance W. Gainer said his department told Byrd to get on the phone with the cabdriver to see if he recognized her voice. He said she wasn't ordered to take any formal tests because such an order is not permitted.

Union officials said Byrd was treated unfairly and should not have been ordered to get on the phone. Six other police officers are on leave with pay while the incident is being investigated. At least one is scheduled to be tested today.

The dispute began when Christopher Johnson, 67, was stabbed in the right eye, nose and left hand after he picked up a fare at Union Station. His car was searched for fingerprints and other evidence, but Johnson later found the knife believed used in the attack under a floor mat.

When he tried to return the knife to police, he said he was rebuffed--first over the phone, then in person. McManus hopes the tests will identify who turned Johnson away.

Gainer said that he supports McManus's request and that the department has asked its own officers to take these tests before, although rarely.

"I don't think the request or being told to get on the phone is outside of the bounds of an investigation," Gainer said. "I am also empathetic that the officers would take umbrage at this, but we have to be complete in these investigations."

Gainer said the tests wouldn't have been admissible in court but would have helped police in the investigation.

"I have not heard of this happening in my years," said Patrick V. Murphy, a former president of the Police Foundation who headed New York City's police department more than 20 years ago. "Investigations into these matters are typically done by comparing written reports by duty officers and others to interviews with police."

The police union wrote a letter to Chief Charles H. Ramsey calling the request "Gestapo-like" and saying it showed lack of respect for the officers.