A young child goes missing, and her parents are in despair.
They make heartfelt televised appeals for the return of their daughter, and the public sympathizes with their plight. But after a few days or weeks, the parents are questioned in the disappearance, the media reports on growing suspicions from anonymous authorities and the public becomes accusatory.
Whether it's the Ramseys, the Aisenbergs or the Smarts, these notorious cases of parents with a missing child seem to follow a similar trajectory, fueled by the media frenzy, as the public mood turns from empathy to suspicion.
Kate and Gerry McCann, the British couple who reported their 4-year-old daughter, Madeleine, missing from their resort hotel room in southern Portugal May 3, are just the latest example of victims turned villains.
Is this change in opinion unfair to the parents in these cases, a symptom of public cynicism and the media obsession with building up and then tearing down their idols? Or is it a reasonable reaction, given the fact that most homicides of young children are committed by their parents?
In the first few weeks, the McCanns' story attracted plenty of sympathy, with neighbors in Portugal putting up posters of Madeleine and Britons holding candlelight vigils praying for the girl's safe return.
But as the search turned up no trace of Madeleine and after her parents were named by police as suspects last week, prompting them to hire a high-profile lawyer, the mood quickly turned and the headlines became vicious.
"Did you kill her by accident" blasted the Daily Mail. "Madeleine: We Can Prove Parents Did It," blared the Daily Express. Even the Help Find Madeleine McCann Web site was flooded with spiteful comments from "I never believed your pain" to "You have shown nothing but cold emotion ever since 3rd May." Another Web site, organized by the McCanns' local newspaper, had to be shut down after it was bombarded with vicious comments.
In the latest twist, despite the fact that Portugal's national police chief deemed inconclusive forensic tests that purportedly found evidence of Madeleine's DNA in the trunk of a car rented by the McCanns five weeks after her disappearance, the public remains suspicious.
In a random sampling of Britons questioned by ABC News, none declared that the couple was innocent and many believed they were guilty of harming their daughter.
Perhaps those reactions aren't surprising considering the statistics on child homicide. Of all children under age 5 murdered from 1976 to 2005 in the United States, 60 percent were killed by their parents and only 3 percent were killed by strangers, according to the Justice Department.
"The younger the child, the more likely the parental involvement," says Robert D. Keppel, an associate professor of criminal justice at the University of New Haven and former chief criminal investigator for the Washington State Attorney General's Office. The results are different in the cases of children who are abducted and murdered, according to a study he conducted.
"Most of those abductions of children who are found murdered, most of them are abducted by people other than family -- neighbors, strangers, everybody else," he says. That makes sense, considering that parents who kill their children usually don't need to abduct them first.
In the case of the McCanns, Keppel says that Portuguese police should have been more proactive in their treatment of the parents. "If the parents are claiming that the kid was abducted, they should have processed them right away for physical evidence -- scars, marks, blood stains on clothing."
Unfortunately, police in these circumstances are often governed by the emotion of the moment, says Keppel. "They veer between two extremes: If they're only treating them as suspects, that can be a problem. And if they only treat them as grieving parents, that can be a problem."
Michelle Oberman, a law professor at Santa Clara University of Law and the author of "Mothers Who Kill Their Children," was also surprised that the police didn't question the parents right away.
"It's the most natural place to start," she says. "The question is why didn't they do this three months ago. The numbers are pretty astonishing, that young children are at greatest risk of homicide by their parents."
One parent who's been in the hot seat, as a sympathetic figure and as a possible suspect, is Ed Smart, the father of Elizabeth Smart. His daughter was abducted at age 14 by a homeless handyman and his female companion and kept for nine months before being reunited with her family in 2003. During the ordeal, the police seized Ed Smart's computer and questioned him and his brothers about Elizabeth's disappearance.
Smart says that he believes in the McCanns and that he talks to Gerry McCann every week, offering him advice and support. "I have been in touch with Gerry ever since the end of July when he came to the U.S. and it was recommended that we talk because of the similarity of our cases," Smart tells ABCNEWS.com.
"In either case, I don't think that the police were trained to deal with the situation, and I don't think that it was done correctly to begin with," he says. Smart claims that the police leak information and innuendo to the media, are prone to tunnel vision and become fixated on a single suspect without following all the leads.
Smart questions some of the recent evidence in the McCann case, including microscopic traces of blood found on the walls of their apartment, saying he's talked to Gerry about it. "He said to me, 'I don't know who's been in the apartment that we've been in -- they might have cut themselves.'"
He also questioned the use of sniffer dogs in the case. "We had 10 dogs when Elizabeth was abducted and they looked at two or three areas of our backyard before losing the scent," he explains. "I don't have a lot of faith in the dogs because of what happened to us."
Smart believes in the innocence of the McCanns: "I do not believe for a minute that anyone who killed their daughter would be staying in Portugal for four months and go on international trips to publicize the loss of their daughter."
The couple also attracts the sympathy of Barry Cohen, the lawyer for Marlene and Steve Aisenberg, the couple once charged with lying about the 1997 disappearance of their infant daughter, Sabrina.
"Accidents happen and it's a tenable theory that the parents panicked and concocted this story about a kidnapping and went to dispose of the body," he explains. But Cohen questions the evidence: "How do you get blood in the rented car if the girl wasn't in that car?"
Cohen says that some police investigators just rely on one piece of evidence. "The problem is that they don't look anywhere else," he says. "They shoot an arrow and draw a circle where it lands."
During these cases, especially the JonBenet Ramsey saga, the media has been criticized for its relentless questioning and breathless coverage. But it seems to play a dual role, sometimes helping and other times hindering the investigation.
"I know the media has done a lot of good in these cases," says Ed Smart, explaining that the press plays a crucial role in reeling in potential witnesses. "For someone missing a child, you can't do it without the media."
Gerry McCann's sister, Phylomena McCann, had mixed feelings about the media's involvement in the case. Some journalists, she told BBC Radio 4, "overstepped their mark." Yet, "If it hadn't been for the help of the media, she says, "Madeleine's case might have disappeared."
Studies show that the media only play a useful role some of the time. "Thirty percent of the time, the media was helpful in advancing the investigation," says Keppel, who conducted a study on the effects of media coverage. "They publicize what went on, and a viewer who saw something calls in. But that means that 70 percent of the time, the coverage was not necessarily helpful."
Clay Calvert, a professor of journalism and law at Pennsylvania State University, says that these types of stories are made for the world of 24/7 journalism on the Internet and cable TV. And part of that appeal, he explains, comes down to the audience playing detective and questioning the motives of parents like the McCanns.
"We know that initial suspects always tend to be those who are closest," says Calvert. "It makes for perfect tabloid fodder. We all love to second-guess the responses and to find the most sinister intentions lurking in people."
Calvert attributes part of this reaction to the counterintuitiveness of these cases. "Here we have another beautiful blond girl who's missing," he says. "And the parents are clean-cut-looking people. How can anybody do anything like that to such a beautiful girl?"
In the end, he believes, the media don't usually help the investigation. "It's interesting to speculate, but we're not really solving the crime. Maybe more energy should be devoted to that and less to running stories about every aspect of the characters in the middle of this tragedy."
ABC's Maeva Bambuck contributed to this report.