An attorney for two Filipino nurses accused of poisoning nine Veterans Administration hospital patients said today defense lawyers may file another motion to dismiss the case because of reports another woman claimed responsibility for the crimes.

Attorney Thomas C. O'Brien told United Press International the revelation raises the question of whether the federal government whithheld evidence from the defense in violation of a court order.

Such a ruling by U.S. District Judge Philip Pratt would wipe out charges for the poisonings, two of them fatal, against Filipina Narciso, 30, and Lenora Perez, 32.

They are accused of injecting pavulon, a powerful muscle relaxant, into intensive care patients at the VA hospital in Ann Arbor in July and August, 1975. More than 40 other mysterious breathing failures were reported during that time.

The Detroit Free Press reported today that Betty Jakim, 51, a nursing supervisor at the hospital, told her psychiatrist prior to her suicide Feb. 3 that she was responsible for the poisonings.

When she died of overdose of transquilizers in Sebring, Fla., the Free Press said, she left a note insisting the defendants were innocent.

The note reportedly is in the possession of Mrs. Jakim's husband, Emil, who has discussed it with friends but not shown it to federal authorities, the newspaper said. He could not be reached for comment.

Prior to her death, Mrs. Jakim reportedly suffered severe depression and was confined for a time to an Ann Arbor mental hospital. The Free Press said her verbal confessions were not reported to authorities because doctors concluded her guilt was a delusion produced by mental illness.

The newspaper said Mrs. Jakim was a suspect in the 11-month FBI investigation of the case, but she was dropped because she wasn't at the hospital each time a breathing failure occurred.

The FBI is opening a new probe of Mrs. Jakim, the newspaper quoted agents as saying. The FBI and prosecutors said they had no knowledge of the Jakim statements or of her suicide note.

But lawyers defending the two nurses have subpoenaed the FBI for all material in the case, including psychiatric records, relating to Mrs. Jakim. Defense attorney O'Brien said government officials have never told defense attorneys details of their investigations fo Mrs. Jakim. Earlier this year Pratt admonished assistant U.S. attorneys for withholding information favorable to the defense.

"Depending on what's been withheld here," O'Brien told UPI, "I wouldn't be surprised to see us ask for a dismissal. It's now possible the case could be thrown out."

Richard Yanko, the assistant U.S. attorney heading the VA prosecution team, said all FBI evidence covered by Pratts order had been turned over to the defense. But Yanko said the FBI had some material on Mrs. Jakim that was never turned over to the defense because it was not covered by the order.

Jury selection in the case was scheduled to resume Tuesday, but attorneys said Pratt may call a special meeting Monday to discuss the latest developments.