Prime Suspect

Billy Fox, 33, is a devoted father of two and a soccer coach. He appears to be an all-around regular guy from Wichita Falls, Texas, with full custody of his children, Skylar and James.

But now, he's about to turn himself into the police, as they book him for the death of a baby. It's a charge that could put him in prison for the rest of his life.

"What attracted me so much to Billy is what a wonderful father he was," says Billy's girlfriend, Cassie Herring, who first met Billy in 2000 -- just a few years after his divorce.

At the time, Cassie was raising two children of her own: Peyton was 2 and Cameron was a newborn.

In a matter of months, they all were under one roof. But in less than six months, startling events would shatter this new family. Correspondent Susan Spencer reports.

Billy, who says he was folding clothes on the kitchen table, asked his son James to bring Cameron to the kitchen. James tripped on his shoelaces and Cameron's head hit the kitchen floor – it was concrete covered by a layer of tile.

"Cassie was getting frantic," recalls Billy. "Because we heard them hit, it sounded like they hit hard."

They rushed Cameron to the emergency room at United Regional Health Care. Cassie says the doctors said there was nothing wrong with Cameron: "I knew something was wrong. I remember his eyes rolled in the back of his head. And that really scared me. And he had some foam coming out of his mouth."

X-rays showed no skull fractures. Doctors told Cassie her son would be fine – and to bring him back if his condition worsened.

"I felt reassured by the doctor," says Billy. But the next day, Cameron just wasn't himself.

"It's like he doesn't even know who we are. It's like he has amnesia," says Billy. But they didn't think about going back to the doctor. "I just went with the understanding that he said he's going to be a little groggy."

Two days later, on Sunday, around 5 p.m., Cassie and Skylar decided to go shopping. When they left, Billy and Peyton were on the couch watching cartoons. Cameron was asleep in his crib.

"Cameron woke up, so I went back there and got Cameron out of his crib and made Cameron a bottle. And tried to feed it to him," says Billy. Within seconds, he says, Cameron began to have a seizure. He immediately rushed the baby to a neighbor -- a nurse who lived right down the street.

"He just ran in. He was frightened. He was scared to death," recalls Tammy Edwards, who was getting ready for work. "I took the baby from him. And I laid him down over here on the couch-- and I tried to do rescue breathing for him. Each breath that I could not get in, I just looked at him and I said, 'Billy, this is not good.'"

"When he went limp, I didn't know. I'll probably never have another feeling like that in my entire life," says Billy who called 911.

An ambulance arrived in minutes and sped Cameron to the hospital. Cassie raced to the emergency room only to discover that Cameron was about to be flown to Fort Worth, Texas. By the time she and Billy got to Cook Children's Medical Center, there was little hope.

"They gathered us in a room and told us they were going to pronounce him brain dead," says Billy, crying.

Cameron Herring – not yet 8-months-old – died the next day.

"The more that time goes on, the more I think, 'I don't have my baby, I don't have my child and he doesn't have his mommy,'" says Carrie.

Cassie Herring is convinced her son's death is a result of Friday night's fall, when his head struck the kitchen floor.

But neurologist Jeffrey McGlothlin, and other doctors who examined Cameron, are convinced that the baby's fatal injury had nothing to do with the fall.

"Having been dropped two days before doesn't give you the picture that we saw that morning in the intensive care unit," says Dr. McGlothlin.

"They kept telling us, 'Somebody did this, somebody did something to him.' And we kept saying, 'You don't understand. He hit his head on Friday night,'" says Billy.

"It was like their mind had already been made up," says Cassie, who adds that the doctors insisted that Cameron's death was no accident.

Deputy Medical examiner Dr. Marc Krouse agrees: "Somebody in the family killed this child. To me, the evidence is clear and convincing."

After completing his autopsy of 7-month old Cameron, Krouse thinks he can pinpoint how and when Cameron died. "He died from a blunt head injury that was inflicted on early Sunday afternoon. Whoever was around him at the moment he became unconscious is the person you should be looking at."

Billy was the last person with Cameron on Sunday before his fatal seizure, and in December 2001, he was charged with injury to a child. Maximum sentence: life in prison.

"Anyone who knows me knows I would never hurt a child," says Billy.

"What they're going on is an autopsy report that labels this a homicide," says defense lawyer Bob Estrada. "It's already been a hard grueling road for them, on top of having a baby die, then an accusing finger is pointing to them."

But Billy and his lawyer are up against the medical examiner's report, which is a damning document. In fact, Dr. Krouse says Cameron's brain injury was so severe that the baby would have been unconscious just seconds after it occurred.

Therefore, Krouse believes that brain injury could not have happened on Friday – because Cameron never would have survived for two more days.

What does he think happened? "Most likely propelled the child into a relatively soft surface, a padded flooring, couch cushion, mattress," says Krouse. "Kind of an over the shoulder motion -- like the guys do spiking a football or slam dunk."

"I loved Cameron with all my heart," says Billy, who denies having a freak accident or a sudden outburst of anger.