It's now been more than six years since foster child Rilya Wilson went missing, a disappearance that led to a shakeup at Florida's child welfare agency and murder charges against the little girl's former caretaker.

Yet Rilya's body has never been found and there's little physical evidence against the woman accused of abusing and killing her, 61-year-old Geralyn Graham.

Faced with no firm evidence that a slaying occurred and no witness who can definitively identify Graham as the girl's killer, prosecutors have been assembling a largely circumstantial case, according to case records reviewed by The Associated Press.

Police dug up Graham's backyard looking for clues. They treated rooms in her house with a substance that reveals hidden traces of blood. They searched the house from top to bottom more than once.

"I found absolutely nothing," Miami-Dade County homicide detective Sara Times said in a court deposition.

Despite the murder charges, Rilya is still listed officially as missing by the state Department of Children & Families. If she lived, she would have turned 11 on Sept. 29.

Graham, who maintains her innocence, remains held on $250,000 bond after completing a sentence on an unrelated motor vehicle fraud conviction. Her attorney, Michael Matters, said he expects prosecutors to seek the death penalty in Rilya's death.

Rilya — whose name stands for Remember I Love You Always — was living as a foster child with Graham and her companion, Pamela Graham, when she disappeared in late 2000 at the age of 4.

It wasn't until April 2002 that state officials discovered she was not at the Graham residence, which ultimately led to the resignation of the Florida Department of Children and Families' chief and to passage of a new law requiring improved supervision of foster children and tracking of efforts to find missing kids.

Pamela Graham, who is cooperating in the murder investigation, said Geralyn Graham told her one day in December 2000 that Rilya was "gone. You cannot see her anymore."

Pamela Graham insisted that she doesn't know what happened to Rilya. "You think I know more than I know, but I do not know where Rilya is," she told police, according to court documents.

Pamela Graham supported allegations of abuse by Geralyn Graham, including claims that Graham tied Rilya to a bed and locked her in a small laundry room for lengthy periods as punishment for misbehavior. Other friends and acquaintances reported similar incidents, as well as unusually numerous bruises, scratches and other injuries suffered by the girl.

One friend, Detra Coakley, said she gave Geralyn Graham a dog cage with the understanding that Rilya would be kept inside it, though she's not sure if it ever happened.

Fellow inmates at the Miami-Dade County jail have told investigators that Geralyn Graham confessed to smothering Rilya and somehow disposing of her body. One of those informants, career criminal Robin Lunceford, has refused to testify or cooperate since she was sentenced to life in prison on a robbery charge.

Geralyn Graham has a long history of fraud and other crimes. Police discovered when she was arrested that she has used 47 aliases and was carrying 10 drivers licenses from Florida and Indiana.

She says she is no killer.

"I realize that I am charged with the most heinous of crimes," she wrote in a May letter to the judge presiding over her case. "I also know it's all hearsay and I've never hurt a soul in my life. I've been guilty until proven innocent and that's not the American way."

Miami-Dade prosecutors said they are ready to take the case to trial even without more physical evidence or the discovery of Rilya's body.

"We would not proceed in this case unless we thought we could prove it beyond a reasonable doubt," said Ed Griffith, spokesman for Miami-Dade State Attorney Katherine Fernandez Rundle. "We have more than enough to go forward."

Matters said he is still poring over some three-dozen boxes of evidence and has many witness depositions to take, including those of child welfare officials. He said investigators kept both Grahams under constant surveillance and even regularly dug through their household garbage looking for clues.

"There's no issue about whether it will go to trial. I would really hope for the opportunity to try this case sometime towards the end of next year," Matters said. "You don't want to speed through something and get a bad result."