Prosecutors filed a murder charge Thursday against the man accused of imprisoning his daughter for 24 years and fathering her seven children, saying one of the youngsters who died in infancy might have survived if brought to a doctor.
Josef Fritzl "deliberately decided not to intervene" and save the infant's life, said the indictment, which also charges the 73-year-old retired electrician with rape, incest, false imprisonment and enslavement.
Officials said they expected Fritzl to go on trial in March. He faces up to life imprisonment if convicted of the murder charge. Austria, like other European countries, does not have the death penalty.
Fritzl's lawyer, Rudolf Mayer, told reporters he would not appeal the charges.
Investigators say Fritzl has confessed to imprisoning and repeatedly raping his daughter Elisabeth — now age 42 — in a warren of soundproofed, windowless cellar rooms he built beneath his home starting in 1984, shortly after she turned 18.
Police say Fritzl told them he tossed the body of the infant boy into a furnace in 1996 after the baby became ill and died. They say DNA tests have confirmed he is the biological father of the six surviving children.
Although nothing remains of the incinerated infant, prosecutors said they based the murder charge on interviews with Fritzl's daughter. They did not release details on the baby's fatal illness, saying only that Fritzl refused to take action "despite the baby's life-threatening situation."
Prosecutors have said a psychiatric evaluation showed that Fritzl is mentally competent to stand trial. They reiterated that stance Thursday but recommended that Fritzl be moved to a special facility for mentally disturbed offenders so he can get counseling.
Prosecutors also said it will be the first time that an Austrian is tried on a slavery charge.
Fritzl imprisoned his daughter and the children beneath his apartment building in Amstetten, 120 kilometers (75 miles) west of Vienna.
Authorities say Fritzl brought three of the surviving six children upstairs to live otherwise normal lives, and claimed to his wife and neighbors that his daughter — who he said had run away to join a religious cult — had left them on the family's doorstep.
The three other children remained imprisoned along with their mother until last April, when one of the youths — a teenage girl — became ill and was taken to a hospital.
Officials said it was the first time the three imprisoned children had ever seen sunlight.
Fritzl, the 27-page indictment alleges, subjected his daughter to "multiple attacks" and terrorized her with threats that the cramped underground cell was rigged with booby traps to foil any attempts to escape. Fritzl also threatened to release poisonous gas into the homemade prison, the indictment said.
It said the daughter was completely dependent upon Fritzl for her survival and had no choice but to provide "sexual services," the indictment added.
Police say they have no evidence to suggest that his wife was complicit.
His daughter, the children and Fritzl's wife have been getting counseling at an undisclosed location.
The case drew international attention to Austria, in part because it was reminiscent of another high-profile imprisonment case.
Natascha Kampusch was kidnapped as a 10-year-old while walking to school in Vienna. She was held in a windowless cell for 8 1/2 years but staged a dramatic escape in August 2006 while her captor was distracted by a phone call.
Kampusch, now 20, is a TV talk show host.