But his father, Patrick Tilt, was apparently distraught at the possibility of having to care for a sick child. One night, Andrew's dad got up in the middle of the night. He later confessed to squeezing the boy until he stopped breathing. He then returned his son to his crib.

Andrew had nine broken ribs when doctors performed an autopsy.

A jury found Tilt guilty of murder and sentenced him to five years to life in prison.

Some cases, like Andrew Tilt's, are clear-cut. As clear-cut as a child homicide case can be. Others are not.

Consider these three sets of circumstances.

• In the late 1990s, a Davis County woman had three babies allegedly die of sudden infant death syndrome within 22 months.

Statistically, experts say, it is impossible to have three SIDS deaths in one family. A forensic expert was prepared to testify that all three were homicides. Law enforcement and child advocates were suspicious of the deaths and pressured the Davis County Attorney's Office, but officials there never did file criminal charges in any of those cases.

• This week, Utah County prosecutors continue to investigate the death of a 7-month-old girl who died in her parents' arms last Jan. 31. A day earlier, her 13-year-old baby sitter said the baby had fallen from a couch or bed. But an autopsy showed the infant died from head wounds inflicted by shaking.

Utah County prosecutors are considering filing child-abuse homicide charges against the baby sitter.

Deputy Utah County Attorney Chris Yanelli calls it a heartbreaking case. The teenager, he says, is a good girl who has never been in trouble. She burst into tears both times Yanelli has gone to speak to her.

• Little Breanna Loveless had bruises all over her body when she died Feb. 23, 1996. She was 9 months old. A number of her bones were broken. She was underweight and had a tear behind her left ear, and she had been tortured. The problem for investigators was the only cause of death identified in the autopsy was "pneumonia."

Prosecutors were left to determine who tortured her and how she died.

"These are tough, tough cases," said Kristin Brewer, director of the Office of the Guardian Ad Litem.

"Most child abuse homicide cases involve a lot of very complicated medical testimony," said Assistant Utah Attorney General Craig Barlow, who heads the Children's Justice Division.

"Another great challenge is the probably laudable instinct most people have — that no one knowingly or intentionally would harm an infant."

Yasmin Moody, 3, traveled the country with her mother and stepfather.

She lived in nine cities in seven states from Florida to Utah through her short life. Along the way, Moody was beaten and tortured.