(CNN) -- An Austrian man who allegedly held his daughter as a sex slave for 24 years has been charged with murdering one of their children, prosecutors say.
Josef Fritzl is accused of fathering seven children by his daughter during her 24-year captivity.
Austrian State Prosecutor Gerhard Sedlacek told CNN Thursday that Josef Fritzl, 73, was charged with murder because one of the seven children died in infancy. The other six children survived.
Fritzl, a retired electrician from Amstetten, 75 kilometers (46 miles) west of Vienna, was also charged with rape, incest, false imprisonment and slavery.
The murder charge stems from the death of Fritzl's infant son, Michael Fritzl, who died from lack of medical care, the prosecutor said. Watch as Fritzl is charged with murder »
"Although he realized how life-threatening M.F.'s situation was after being born, Josef F. did not call out for help," Sedlacek said, explaining the charge.
The trial is expected to begin early in 2009 and if convicted of murder Fritzl could face 10 to 20 years in prison. Austria, like other European countries, has no death penalty.
Prosecutors say psychiatric tests show that Fritzl is mentally fit to stand trial but Sedlacek has asked that Fritzl be confined to a "mental asylum."
Fritzl kept the daughter and all but three of the children in a cellar beneath his home in Amstetten, Austria, west of Vienna, officials say.
Three of the children lived upstairs in the home Fritzl shared with his wife and several of their own children.
Fritzl has been in custody since the case came to light in April, sparking worldwide attention.
He had explained Elizabeth's disappearance in 1984 by saying the 18-year-old girl had run away from home, a story backed up by letters he forced Elisabeth to write, including one that begged her parents not to look for her.
When Elizabeth gained her freedom, she told police her father began sexually abusing her at age 11. On August 8, 1984 -- weeks before she was reported missing -- her father enticed her into the basement, where he drugged her, put her in handcuffs and locked her in a room, she told police.
For the next 24 years, she was constantly raped by her father, resulting in seven children, she said, according to the police statement.
Fritzl's daughter and her children have since been receiving counseling although doctors warn that they will take years to recover.
Members of the Fritzl family will also be offered the chance to adopt new identities in an effort to help them lead normal lives, officials said.
Psychiatrist Max Friedrich, who treated the abducted Austrian teenager Natascha Kampusch, estimated it would take "between five and eight years" for the children to recover from their experiences.