HAYWARD, Calif. (AP) _ A woman charged with child abuse for dressing her son like a pig lost an infant 11 years ago when he was beaten to death by his father, authorities said.

Alameda County Deputy District Attorney Angela Backers said Thursday it is too early to tell how the disclosure will affect the case against Mary Francis Bergamasco.

Bergamasco, 28, pleaded innocent earlier this week to a charge of child abuse.

She was arrested last week when when police found her 7-year-old son tied to a bench in front of their home.

Police said a crowd of neighbors had gathered to view the crying boy. His face was painted blue and a pig's snout fashioned from an egg carton was taped to his face. A sign hanging on his chest explained that he was being punished for stealing and lying.

The boy and his two sisters have been placed in foster homes.

Reached at Bergamasco's home, her sister, Debbie, said the woman was not available for comment.

''She's on the verge of a nervous breakdown,'' the sister said.

The woman's first son, 3-month-old Douglas Betts Jr., died April 29, 1977, after suffering a fractured skull, a broken back and other injuries.

Lawrence Martin, the Fountain, Colo., police detective who investigated the case, said the child's father, Douglas Betts, pleaded guilty Dec. 2, 1977, to charges of second-degree murder. Betts, at that time a soldier stationed at Fort Carson, Colo., served three years in prison.

Backers said she has informed both county child protective services and the probation department about the Colorado case.

''It may affect her eligibility for counseling'' through a probationary program, the prosecutor said.