06/07/2011 AT 05:40 PM EDT
Several people have testified to the foul smell of decomposition in and near Casey Anthony's trunk after 2-year-old Caylee was reported missing in July 2008. In court Tuesday afternoon, jurors heard about a specially trained non-human's detection of the odor: a German Shepherd named Gerus.
Deputy Jason Forgey, a cadaver dog handler with the Orange County Sheriff's Office K-9 unit, testified that Gerus alerted officers that there had been a dead body in the trunk of Anthony's car.
"He's taught to detect human composition," Forgey testified, "specifically cadavers."
Forgey testified that he first got the call on July 17, 2008, to have Gerus smell Anthony's white Pontiac Sunfire, which was being kept at a police impound lot. As Forgey and Gerus went counterclockwise around the car for "the first pass," Gerus "started indicating," testified Forgey. "I opened the door and he tried to get into the trunk from the back seat."
Forgey and Gerus then went to the back of the vehicle. "Gerus stuck his head in the trunk," Forgey continued. "At that point, I was also overwhelmed by the smell. And then Gerus gave me a trained final alert." According to Forgey, Gerus indicates a "final alert" by sitting down and making eye contact with his handler.
Forgey then took Gerus to the Anthony family home to inspect the backyard. "He gave a trained final alert by the play area," says Forgey. "By the playhouse and sandbox."
As the prosecution showed a picture of the playhouse, Anthony had no reaction.
Under cross-examination, defense attorney Jose Baez asked Forgey why he didn't videotape the search. He also questioned whether Gerus had another agenda to make the alerts. "The dog wants to please you," said Baez. "That's his motivation."
"I suppose that's right," answered Forgey, as jurors took notes.
Baez also introduced evidence that Gerus did not indicate the presence of a body on the spot where Caylee Anthony's remains were found – in a wooded area near her grandparents' home.
For the first time of the day, Casey Anthony reacted to the testimony, nodding her head.