PORTAGE, Wis. -- Investigators are continuing to piece together what happened after police uncovered a dead body and several mistreated children at a Portage house last week. Three people were arrested.

SLIDESHOW: View Images Of Portage Investigation

More details are expected to come to light later this week, WISC-TV reported.

An autopsy this weekend found that a 37-year-old mother who was found in the back yard of house died of "manual strangulation." The autopsy also identified multiple injuries on the woman consistent with physical abuse, according to Columbia County medical examiner Marc Playman.

Police were originally called to the home in the 300 block of Onedia Street on a report of a child abduction. The National Center for Missing and Exploited Children told Portage police that Courtney Alisa Clark, a 2-year-old from Orlando, Fla., who had been missing since last September, might be at the home with her mother who didn't have custody.

Portage police said they found the missing 2-year-old at the home on Thursday and that the child was OK, WISC-TV reported.

While at the home, authorities said they found physical evidence that an 11-year-old boy was the victim of serial physical abuse and malnutrition. The boy was found locked in the closet with severe burns on his face, hands and feet. The abuse was allegedly in the form of being burned with scalding water. Besides that, authorities also discovered head wounds, burned fingers and toes and scratches to the torso on the boy. The child had also been educationally neglected.

Police said that the abuse was punishment for failing to clean. The boy is currently in guarded condition in a hospital, authorities said. Portage Police Chief Ken Manthey said the alleged torture was the worst he had seen in 30 years as an officer.

During their investigation, the boy's 15-year-old sister tipped authorities on Friday to search the back yard for her mother. Police said that they believe the woman might have been dead since Memorial Day weekend.

Police said that they also found two other children in the house, a 1-year-old girl and 3-month-old girl. The youngest girl had evidence of malnutrition as well, police said.

Police haven't filed any homicide charges yet, but three people -- all adults apparently living at the residence -- are in custody.

Michael Sisk was arrested in Milwaukee on Friday and is being held on a tentative charge of causing physical harm to a child. Two women -- Michael Clerc, 20 and Candace Clark, 23 -- are also being held under the same charge. All three are expected to make a court appearance on Wednesday afternoon, WISC-TV reported.

Florida Officials Ask Questions

Authorities in Florida are questioning why it took so long to report the abduction of the missing 2-year-old girl.

Authorities in Pinellas County now said that a caseworker waited more than four months to report Courtney Alisa Clark as missing.

Florida investigators said that the girl had been given to a foster mother in September after the girl's mother, Candace Clark, was arrested on identity-theft and fraud charges. Ten days later, the mother reportedly took the girl from the foster mother and disappeared.

A child-welfare agency prepared a report but investigators said that it was never distributed. Four months later, a caseworker reported the girl missing.

Stay tuned to WISC-TV and Channel 3000 for continuing coverage.