PLEASANTON, Calif., Apr. 10 — Would-be presidential assassin Lynette “Squeaky” Fromme will be moved back to a federal prison in Alderson, W. Va. as punishment for striking an inmate with a hammer, prison officials said Monday.

A prison investigation found Ms. Fromme, 30, was guilty of assaulting inmate Julienne Busic with the claw side of a hammer while the pair gardened on the prison grounds.

Gene Boris, public information officer for the Federal Correction Institute here, said Monday Ms. Fromme would be moved in two or three weeks to a women’s prison in West Virginia as a direct result of that incident.

Ms. Fromme served 2 1/2 years in the West Virginia prison after her conviction for trying to assassinate President Ford in Sacramento in 1975. She was moved to Pleasanton last June after West Virginia prison officials said she was a “model inmate.”

“Sometimes people can get along better in one place than another,” Boris said.

“Any time that an inmate cannot handle the institution that they’re in, behaviorally, etc., then we have the option to move them to another institution.”

Ms. Fromme has been isolated since the March 8 incident.

Boris said she will be housed in isolation at Alderson as well. She will be in the same high-security building where Sara Jane Moore, convicted of a second attempted assassination of President Ford, is also living in isolation.

Ms. Fromme, a follower of convicted mass murderer Charles Manson, told the Associated Press in a letter after the assault that Ms. Busic “is a rat, was Patricia Hearst’s best friend and (was) very disrespectful to me.”

The government decided earlier this month not to prosecute Ms. Fromme in the assault.