APPLETON, Wis. (AP) _ A baby sitter was charged Wednesday with murder in the deaths of three infants who died since 1980 in her home, where children testified they saw her place towels on the faces of crying babies.

Sandra Pankow, 36, who declined to testify last week during an inquest, was named in a complaint signed by Outagamie County District Attorney William Grogan on three counts of second-degree murder. She was jailed in lieu of $60,000 bond - $20,000 on each count.

Deaths of the three children originally were ruled sudden infant death syndrome, or crib death.

After Tyler J. Kloes, 6 months, died Oct. 25, Grogan decided to re-open the cases of Kristin Hamilton, 14 months, who died Dec. 29, 1980, and Shawn M. Bloomer, 9 months, who died Aug. 10, 1982.

Forty-two witnesses, including several children in the woman's care, testified at the inquest.

Children who had been at Mrs. Pankow's home testified that they saw her place towels over the babies' faces when they cried.

Enid Gilbert, a pediatric pathologist at the University of Wisconsin and an authority on crib death, testified that she believed the children were suffocated.

Parents told how small children were frequently kept in the unfinished, damp basement of the Pankow home, but Mrs. Pankow's husband, Doug, and her son, Christopher, 14, testified that no children were kept in the basement.

They said they had no knowledge of towels being placed over children's mouths.

Mrs. Pankow cited her Fifth Amendment rights against self-incrimination when she refused to testify. Her husband and son testified after being granted immunity from prosecution.

A six-member inquest jury's recommendation of the charges ''was an advisory opinion, but certainly was entitled to great weight,'' Grogan said.

He said he also consulted with police and with members of the young victims' families before filing charges.

Mrs. Pankow faces up to 20 years in prison for each count if convicted.

The jury was given the option of recommending charges of first-or second- degree murder, negligent homicide or child neglect leading to death or finding that the infants had died of natural or accidental causes.