Casey Anthony trial dragged on to day 21 with the defense taking a odor detected in Casey's car was not necessarily from decomposition of Caylee's body even as the lawyers for both sides turned nasty, Friday, and verbally went for each other's jugulars, prompting the judge to issue them a stern warning.

University of Concordia, Nebraska, forensic entomologist Dr. Timothy Huntington testified Friday that the odor that the prosecutors detected in the trunk of Casey's Pontiac Sunfire did not necessarily come from the decomposition of the body of the 2-year old toddler as the prosecution alleges.

He also said the discovery of a fly leg in the trunk of Casey's car was not significant.

The evidence doesn't make sense that there was a body in the trunk, Huntington said.

The defense expert also said the stain found in the trunk of the car was not stain from human body decomposition.

Huntington said he has researched on decomposing pigs inside car trunks and found that blow flies were drawn to the decomposing bodies of the animals. A pronounced stain was also left behind on the carpeting of the car's trunk by the decomposition fluid that was released from the dead body.

If indeed Caylee's decomposing body was in Casey's car, you expect to find many flies, Huntington said.

If we assume a body is in a car trunk, you would expect to find hundreds if not thousands of these blow flies, he said. They're in there. They die there. They're stuck there.

The entomologist also said the stain left behind by a decomposing body is no ordinary stain that can be cleaned easily. It is a sticky, greasy, disgusting material, he said. Once it soaks in there, I'm not sure a professional cleaner could get it out.

Huntington said the smell in the trunk possibly came from trash that had been inside the car and not from decomposing human body as alleged by the prosecutors. He also disputed the notion presented by the prosecutors that paper towels found in the garbage bag that had been in the trunk had decomposition fluid on them.

However, on cross examination by prosecutor Jeff Ashton, Huntington acknowledged that it is possible that in Casey's case, there was a decomposing dead body in the trunk of the car which was not accessible to blow flies. He said it is also possible that the body could have been left to decompose somewhere for 2-3 days before it was disposed off in the woods (prosecutors say Caylee's body was dumped in the woods 3-5 days after she died).

Huntington also acknowledged that this was the first real case involving a dead human body suspected to have been in a car trunk that he has come across.

When asked by Ashton whether it is true that none of the studies involved wrapping a child in a blanket, stuffing the child in two plastic bags and a laundry bag, Huntington replied in the positive.

The entomologist also acknowledged that there was no apparent food source or garbage in the car that could have attracted the flies.

Huntington also recalled having examined Casey's car two years after Caylee went missing, with the garbage removed and the trunk lining ripped out, and said it still smelled bad. He also could not cite an example where the stench of garbage would linger for two years.

Ashton also attempted to undermine Huntington's testimony by suggesting that his research on dead pigs had no bearing on Caylee's case. Why didn't you wrap your pigs in a blanket? Ashton asked Huntington, drawing laughter from the audience in the courtroom.

Huntington's testimony is significant as prosecutor's witness and forensic entomologist Dr. Neal Haskell had earlier testified that the investigators had found bugs and maggots in the trunk of Casey's car as well as on the site where Casey's remains were found. Haskell said such insects are linked to decomposing dead bodies.

Several other witnesses, including Casey Anthony's parents, had also testified the Pontiac smelled as if a dead body had been inside.

On Friday, tempers also flared in the courtroom as Ashton and defense lawyer Jose Baez verbally went for each other's jugular.

Ashton had attempted to undermine Huntington's testimony by saying he is not an expert to testify on decomposing fluid. The prosecutor also said Huntington's opinion on the stain could not be admitted in court as he did not include his opinion on the stain in his report.

It made Baez testy and he insisted that Huntington was only going to tell the jury what he would expect to see in a trunk that had a decomposing body in it for several days, not offer his opinion on what the stain in this case was.

It prompted Judge Belvin Perry to issue a stern warning to both. Perry told them to calm down or risk being held in contempt of court.

I do not, I do not want to hear editorial comments, Perry told Ashton. I don't care what Baez is doing or not doing...I do not care if Mr. Baez was standing on his head.

Perry allowed Huntington to speak generally on decomposition fluids and their characteristics in general, including staining. However, Huntington was not be allowed to speak specifically about the stain found in Casey's car because he did not examine it directly and also because the prosecution was not informed that he would give his opinion on the matter.

Meanwhile, surprise defense witness Vasco Thompson refused to testify in court and in a media conference on Friday, said he had no links to Casey's father George Anthony. The defense claims Thompson, who has a criminal record and was in prison for 10-years, knows George and several phone calls were traced between them around the time Caylee disappeared.

Thompson's lawyer Matt Morgan said Casey's lawyers are trying to make his client a scapegoat to create doubts in the mind of the jury.

Thompson said he didn't have the the phone number in question until February 2009 or two months after Caylee's remains were found. I have no idea who George Anthony is, Thompson said. I've just seen him on TV. I've never talked to George Anthony.

I don't know why they got me involved in all this mess, he said.

Thompson's lawyer also said the 10-year prison sentence sprang from a kidnapping charge. Thompson was arrested in 1987 following a domestic dispute with his former girlfriend. “It wasn’t like he kidnapped a child and thrown it in the back of a car,” Tampa Bay Online quoted Morgan as saying.

The trial will resume on Saturday.

About Casey Anthony Trial

Two-year old Caylee was last seen alive on June 16 and it was only on July 15 that she was reported missing by her mother Casey Anthony to the police. Cindy, Casey's mother had also alerted the police by calling a 911 dispatcher and saying that she had smelled a dead body in the trunk of Casey's car that was spotted in an impound lot. The car was later towed by authorities for forensic analysis.

Initially, Casey told the police that a babysitter called Zenaida Fernandez-Gonzalez (Zanny the nanny) had abducted Caylee. Investigations showed Casey was lying as the babysitter Zanny was fictitious. Five months later, in December 2008, Caylee's decomposed skeletal remains were found in a wooded area near the Anthony home by a meter reader who was relieving himself.

The prosecutors say Casey chloroformed Caylee and then put duct tape over her nose and mouth, suffocating the girl.

Casey's lawyers claim Caylee was not murdered. They say the toddler accidentally drowned in the family swimming pool and George, Casey's father, helped her keep the death a secret. George has denied the claim.

Casey has been charged with seven counts, including first degree murder, aggravated child abuse and misleading the police in the death of Caylee. If she is convicted of first degree, she could be sentenced to death by the seven-woman, five-man jury. The trial is expected to take another 2-3 weeks before a verdict is reached.