(CNN) -- Now that Caylee Anthony's remains have been identified, the search for the Florida toddler turns into a prosecution of her mother.
Casey Anthony, 22, is accused of killing her daughter. Investigators say her alibi didn't check out.
Although Orange County, Florida, Medical Examiner Jan Garavaglia said Friday she could not determine how Caylee died, she concluded the death was a homicide.
The child's mother, Casey Anthony, 22, faces charges including murder in the disappearance and death of Caylee, who was 2 when she vanished last summer.
The remains were found last week in woods about a half-mile from Anthony's parents' house and identified through DNA testing. See where Caylee's skeleton was found »
On Saturday, investigators finished 10 days of sifting through the crime scene and served a warrant at the Anthony house for a third search for evidence, said Capt. Angelo Nieves of the Orange County sheriff's department. Cindy and George Anthony, the child's grandparents, were present for the search.
The mother's defense team had claimed since her October indictment that the child might still be alive, even claiming witnesses spotted Caylee since her disappearance.
The finding of the body "has really cut the legs out of the defense," Stacey Honowitz, an assistant Florida state's attorney, said Friday night on CNN's "Larry King Live." Watch experts size up the legal case »
The lack of a cause of death and the absence of any soft tissue on the toddler's skeletal remains poses a challenge for prosecutors, forensic expert Lawrence Kobilinsky, a defense consultant for Casey Anthony, told Larry King.
"If you don't have a cause of death, isn't it possible that it might have been an accident?" Kobilinsky said.
A murder conviction would require proof the victim was killed intentionally. Legal experts say duct tape reportedly found on the body could convince a judge or jury that Caylee's death was not an accident.
Perhaps of greater significance, though, is Casey Anthony's behavior since -- and even before -- her child went missing.
According to earlier reports, Caylee was the result of an unintended pregnancy, and Anthony made an attempt to give her up after birth. She referred to Caylee as "the little snot head" and continued to maintain an active social life. Follow a timeline of the case »
When Caylee went missing, Anthony did not tell her family for a month. It was the child's grandmother who called police. Anthony told conflicting stories at the beginning of the investigation, including a tale that Caylee was with a nanny. The name and address turned out to be bogus. As police searched for Caylee, they say Anthony's active social life continued -- including one memorable evening dancing at an Orlando bar that was hosting "Hot Body Contest."
Investigators said they found the scent of decomposing flesh and a trace of chloroform, a powerful knockout agent, in the trunk of a car Anthony drove at the time. Anthony's family offered various explanations, including a rotting pizza and a dead squirrel. Watch a tribute to the little girl »
On the Anthonys' home computer, police found there had been searches for chloroform, missing children and "neck-breaking," although Garavaglia said Friday that she did not find evidence of trauma to the bones.
"The prosecution is going to have a great deal of circumstantial evidence, and this is a physical evidence case," Kobilinsky said. "This is not a question about credibility, although obviously a jury looks at credibility and contradictions, but the physical evidence will either include her or exclude Casey. It's an uphill battle for the defense."
Nevertheless, forensic expert Kathy Reichs, who also is working with Anthony's defense team, sees an opening.
"Given that there's no evidence as to the cause of death, ... you could have an accidental death and a mother that panics," she told King. "There are alternative explanations."
Perhaps not enough to save Anthony, said famed defense attorney Mark Geragos, who is not associated with the case.
"The defense will try to focus, I'm sure, on all of the forensic evidence and whatever else they can do," he told King. "But they're always going to be up against it with the 'She didn't act right' evidence, and that's the hardest thing to combat in this case."
Prosecutors don't need to show what killed Caylee, Geragos said. The defense needs to overcome Casey Anthony's statements and behavior.
"Somebody is going to have to give an explanation at some point as to when she last saw the child, who she gave the child to," he said. "And until that is done, I don't care what they put together, it's not going to carry any weight."