ORLANDO, Fla. -

While attorneys were arguing whether jurors should hear about the "death smell" in Casey Anthony's trunk, Anthony's attorneys filed a motion calling a previous ruling by the judge biased.

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The defense blasted Judge Belvin Perry for allowing statements Anthony made to deputies and family members after her daughter, Caylee Anthony, was reported missing into trial. It said Perry was biased and incorrect in his ruling. The defense filed a motion Thursday afternoon requesting a rehearing.

Thursday's hearing, continued from Wednesday, focused on the smell of death and whether a Dr. Arpad Vass, a research scientist, will be the first ever allowed in the United States to testify that he and his machines can detect human decomposition in air.

"When I opened the can (an air sample taken from Anthony's trunk), I had to jump back two feet. It was, to me, the smell of human decomposition," Vass said.

Vass ruled out theories about old pizza and a squirrel causing the odor in Anthony's car. He also said he was shocked by the high levels of chloroform pulled from the air in the trunk.

"I have never seen chloroform be the largest in any sample we have ever shot in my 20 years of doing this," Vass said.

Earlier Thursday, the topic of a cadaver dog alerting to a death smell was discussed.

A K-9 named Gerus, and handled by Deputy Jason Forgey, alerted during a search of the Anthony family's back yard and in Anthony's car in July 2008, meaning he indicated a dead body had been in those areas.

Forgey has thousands of K-9 cases under his belt, including more than 100 cadaver dog searches. He testified Thursday that his dog is trained to alert on ground where a body has been moved from.

Anthony's defense team wants the cadaver dog testimony kept out of trial.

The hearing will continue Friday, April 1 and possibly into April 2.

Anthony, 25, is charged with first-degree murder in Caylee's death. Caylee was 2 years old when she was reported missing in July 2008. Her remains were found in a wooded area in east Orange County in December 2008.

Perry said he will not rule from the bench when the hearing is over. He will issue a written order. For now, he has only heard testimony from experts, but no arguments.