A baby girl goes down for a night's sleep. The next morning she's gone, her parents say. No unusual sounds had awoken anyone in the house. There is no damning evidence of break-in and abduction.
And the parents, initially given sympathy and support, are increasingly viewed with suspicion.
Lisa Irwin, the girl who disappeared two weeks ago in Kansas City, Mo.? Yes, but the scenario also applies to Sabrina Aisenberg, the four-month-old girl her parents said was stolen from her crib in November 1997, in Valrico, Fla..
"Our hearts go out to the parents," said Steve Aisenberg, 48. "We're more than willing to talk to them. They're not alone. Our prayers and thoughts are with them every day. … Hopefully, they won't have to wait as long as we have."
The Aisenbergs are still without Sabrina. The police investigation is still open.
No arrests have been made in Lisa's case, and her parents maintain their innocence. Lisa's mother, Deborah Bradley, told ABC News that before Lisa's disappearance, she would always suspect the parents in missing-baby cases. She said she knew she may well be arrested herself.
Marlene Aisenberg, 49, said, "It's a very tough thing. We knew we didn't have anything to do with [Sabrina's disappearance]. And [Lisa's parents] know they didn't have anything to do with Lisa. The hardest thing in the world is having your child taken from you. The second-hardest is being accused of doing something to her."
According to press reports, as the search for Sabrina and/or her abductor went on, the Hillsborough County Sheriff's Office grew more suspicious of the Aisenbergs. It got a warrant to bug their home. State prosecutors chose not to charge the Aisenbergs, but in 1999 a federal indictment charged them with assorted crimes, the most serious being lying and conspiracy. The indictment relied on alleged recorded outbursts between the couple about Steve having killed Sabrina while high on cocaine. The Aisenbergs denied the charges.
A federal judge declared the tapes inaudible and the transcriptions faulty, and in February 2001 the prosecution dropped the charges before the trial had begun. In February 2004 an appeals court ordered the government to reimburse the Aisenbergs almost $1.5 million for defense fees.
The last public events in the case were in 2008. A police informant reportedly said his cellmate had told him he bought a boat from the Aisenbergs as part of a plan to dispose of Sabrina's body in Tampa Bay.
"It's ridiculous to begin with," said Steve. "If police had done due diligence, they would have found that we didn't have a boat or any contact with this person." All it did was "rub salt into an already deep wound," he said.
If as a missing-baby drama unfolds parents are cast in conflicting roles -- victims and suspects -- so are police. They are uniquely equipped and empowered to both find the missing child and solve the mystery of its disappearance, which can mean being helpful to and suspicious of the parents.
Brad Garrett, a former FBI special agent and a consultant to ABC News, said the first decision police face is whether they can eliminate the parents from suspicion. "Sometimes there's not a clear line you can draw," he said.
In these cases what ensues, he said, is "a delicate balance to push parents to tell the truth while not alienating them so they stop cooperating." The key is "good cop-bad cop," a perfect illustration of the aforementioned dual role. One detective stays at the parents' side, protecting them. Another challenges and provokes them. Then they compare notes and look for lies and inconsistencies.
"[The police] don't like doing that; they just have to do it when there's no evidence [leading elsewhere]," Garrett said.
In a recent interview with "Good Morning America" Garrett called police's focus on Irwin's parents "logical." He said Lisa was "probably not" abducted by a stranger -- "statistically and otherwise, it doesn't really fit" -- but an acquaintance, plumber, neighbor or babysitter was more plausible.
Garrett said sometimes missing-baby cases happen when the baby dies by accident and the parent or parents panic and dispose of the body. Usually the disposal is shoddy and the body is found fairly quickly. Therefore, the fact that Lisa is still missing makes it less likely that, if she is dead, she died accidentally, he noted.
"What you're left with is not being closed-minded," Garrett said. "It's easy to put blinders on, the longer it goes on."
The Aisenbergs live in Bethesda, Md. Steve delivers high-tech equipment to ophthalmologists, and Marlene is a real estate agent. "Our children are in college. They're growing up to be great people. We're very proud of them," said Steve. They celebrate Sabrina's birthday. They continue to seek her in various ways. "But we try not to let [Sabrina's absence] consume us," Steve said.
The Aisenbergs still get leads -- there have been eight since March, Marlene said – directly and through the National Center for Missing and Exploited Children, which assists in their search.
"Unfortunately, a lot of them are ones that people have called in before," Marlene said.
"It's been 14 years. We believe she's still alive. It just needs to be yesterday, you know?" Marlene said. They take hope from the story of Elizabeth Smart, who in 2003 was rescued after being abducted for nine months. "It only takes that one lead," said Marlene.
The Aisenbergs also have a private investigator trying to find Sabrina.
In 2003 an Illinois girl was thought perhaps to be Sabrina, but a DNA test was negative. Marlene said there were two promising leads on girls who might be Sabrina, one in California.
Time could be on their side. "Sabrina's 14 now," Steve said. "In a year or two, she'll want a driver's license," for which she will need a birth certificate. But "if someone is willing to take a child, they're willing to create false documentation," he said.
Marlene said they didn't have much contact with the Hillsborough County Sheriff's Office. But, Steve added, they believe it will be with their help that they will be reunited with their daughter. If the crucial break occurs, "they're going to be the ones to [follow it through]."
As to Lisa Irwin's parents, beyond expressing his and Marlene's support for them, Steve said, "Right now what this family needs most is the support of their community." When asked if that was missing when they were in the spotlight now pointed at Irwin's parents, he replied, "It was there, but it also got squashed at certain intervals."
Anyone with information about Sabrina is requested to call the Hillsborough County Sheriff's Office at 813-247-8200.
Anyone with information about Lisa is requested to call the Kansas City Police Department at 816-474-8477.