ORLANDO, Fla. -- New FBI DNA results in the case of a missing Orlando girl indicate the girl is most likely dead.

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IMAGES: Missing Caylee Anthony Photos
IMAGES: Photos Of Casey Anthony Surface

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Hair samples found in the trunk of Casey Anthony's car are likely that of her daughter, Caylee, but Casey Anthony cannot be ruled out yet.

And the hair samples do show signs of decomposition, Local 6 confirmed Thursday.

However, there can be false positive results with the testing, Local 6's Jessica D'Onofrio reported.

Also, preliminary air samples taken from the vehicle indicate the foul odor in the car was that of a dead body.

Casey Back In Jail?

Meanwhile, the celebrity bounty hunter who helped orchestrate the release of Casey Anthony said the woman could be back behind bars within a matter of days.

Leonard Padilla said that he planned to begin the process of revoking Casey Anthony's $500,000 bond and it could be completed either late Thursday or Friday.

"Your position has changed. You believe that Caylee is dead," Local 6 News reporter Louis Bolden said in an interview with Padilla.

"Yes, I do," Padilla said. "The tests from the University of Tennessee -- they said that a human body was in the process of decomposition in the trunk. It's a longshot that it's somebody else."

"You think it's Caylee?" Bolden said.

"Yes," Padilla answered.

"And you think Casey hid the body," Bolden said.

"Yes," Padilla said. "Yes and yes."

Padilla said death threats against Casey Anthony and her family have tripled, so he thinks they would be safer if she was back in jail.

"She kept saying that if she got out of jail that she would help find her daughter. That didn't happen at all," Padilla said. "I've never talked to her. After she got out of the van (on the ride to her parents' house from jail), we've not had any conversation."

Padilla said on Wednesday that he would not have helped free Casey Anthony if he knew then what he knows now.

Padilla said he has had second thoughts in recent days concerning his role in getting her out of jail.

"Had I known that she would not talk to me, coupled with that (discovery) report -- no, I would not have come (to Orlando)," Padilla said.

"You would not have bonded her out?" a reporter asked.

"No, absolutely not," Padilla said.

Padilla said his second thoughts came after reading more than 400 pages of documents made public this week.

"I've never run into a person who lives in a parallel universe and does not have a worry about what has happened to her 3-year-old daughter," Padilla said.

Much of the information had already been released, including that Anthony had told detectives a series of lies and was out partying days after her daughter was last seen, Local 6's Louis Bolden reported.

Casey Anthony was arrested on charges of child neglect and filing a false statement in mid-July, about 31 days after she said she had last seen Caylee.

She was released on bond last week and is currently being monitored by an ankle bracelet while on home confinement at her parents' house.

Anthony has been offered limited immunity by the State Attorney's Office and has until Tuesday to accept the offer, Local 6 News reported.

Decomposing Body In Car

Wednesday, Local 6 reported that evidence removed from a car belonging to Casey Anthony indicated a decomposing body was in the vehicle's trunk.

Detectives now have scientific proof that a body has been in the trunk of Casey Anthony's car, sheriff's office sources confirmed to Local 6's Mike DeForest Wednesday night.

Early in the search for Caylee, Orange County sheriff's detectives took hair and air samples from Casey Anthony's vehicle. Local 6 showed video of CSI taking the samples in a garage.

The evidence was then sent to the University of Tennessee Body Farm -- a place that specializes in human decomposition.

Investigative sources confirmed to Local 6 News that evidence found in the trunk of Casey Anthony's vehicle indicates that a dead body was inside, Local 6's Jessica D'Onofrio reported.

Cadaver dogs initially alerted officials to human decomposition in the trunk before the evidence was sent to Tennessee.

Also, when the vehicle was originally found, Casey Anthony's mother, Cindy, appeared to believe something sinister may have happened to Caylee.

"There is something wrong," Cindy Anthony said in a 911 call. "I found my daughter's car today and it smells like there's been a dead body in the damn car."

However, during recent interviews, Cindy Anthony has claimed that Casey had rotting pizza in the trunk of her vehicle and that was the reason for the foul smell.

The Orange County Sheriff's Office said they will be working with the Body Farm to solidify the latest results.

Investigators are not saying the body inside the vehicle was that of missing Caylee but sources said prosecutors have now offered Casey Anthony a limited form of immunity if she helps detectives locate Caylee, DeForest reported. The offer expires next Tuesday.

Attorney Unaware Of Evidence

Meanwhile, the Anthony family attorney, Jose Baez, said he was not aware of the latest developments until the media brought it to his attention.

He said his focus remains on finding Caylee.

"That is the reason why I'm standing here to let people know that we still have a missing child," Baez said. "The police have specifically told me today that they have not found her and that is why I want people to keep looking for her. It is very frustrating when you hear news like this but it is all speculation."

Reports Being Disputed

After the test results were announced Wednesday, Local 6 received a statement from Anthony family spokesman Larry Garrison.

It states: "Reports surrounding the DNA of Caylee Anthony are being disputed by the family and their attorney."

Garrison said he was just told that Caylee has not been found.

The statement also said the sheriff's department never told them that the University of Tennessee was conducting tests and that has not been confirmed.

The statement also said no plea deal is being discussed.

Watch Local 6 News for more on this story.