Andrew and Hilery Maison were charged with murder, torture and child abuse after authorities say Mackenzie Maison, 5, and her 3-year-old sister were found malnourished, dehydrated and abused.
Mackenzie was found unresponsive Tuesday in a home in Port Huron and pronounced dead at a hospital, while her younger sister is at Children's Hospital of Michigan. Port Huron is 55 miles northeast of Detroit.
Bond was denied and not-guilty pleas entered during video arraignments for the Maisons, who were arrested Tuesday. Hilery Maison denied the charges and asked for an attorney, and Andrew Maison also has no lawyer. The next hearing was set for June 9.
Assistant Prosecutor Mona Armstrong said Mackenzie was 25 pounds at the time of her death, and was also suffering from pneumonia and a genital infection. Her 3-year-old sister weighs 17 pounds. Armstrong described both as "severely malnourished."
Armstrong said two other children removed from the home and placed in foster care appear to be healthy. They are believed to be Hilery Maison's biological children.
"There are two victims in this particular case," Armstrong said, adding that they "severely neglected" and denied food and nourishment over the course of "weeks to months."
An autopsy was completed Thursday, but results haven't been made public. Medical examiners also are awaiting lab test results.
"It's heartbreaking," St. Clair County Prosecutor Mike Wendling told The Associated Press. "It's not the type of case any prosecutor wants to handle, but it has to be handled."