According to Mellich's testimony, suspicions surrounding the Anthony's car began when he noticed a "very bad smell" inside the car during his investigation in the days following Casey Anthony's arrest.
Mellich said hairs of the same length and color of the 2-year-old were found in the trunk, and they've been sent to a forensic lab for DNA testing.
Mellich's suspicions were supported when Officer Jason Forgey, who also testified in court today, and his K9 partner, a "cadaver dog" named Gerrus, searched the car and the dog "alerted to the odor of human decomposition in that car."
Forgey and Gerrus were also among the team that searched the Anthonys' backyard in the days following Anthony's arrest, and though the dog "alerted" to human decomposition there, as well, no body was found.
Mellich questioned family members yesterday concerning Anthony's treatment of Caylee after a tip from a hairdresser corroborated suspicions of abuse he had after seeing a picture of Caylee with a mark under her eye. Each family member said he or she had never witnessed any abuse.
Mellich also revealed during testimony that an unnamed witness believes he talked to Casey Anthony on the phone while she was in contact with Caylee as late as June 24 or 25 -- more than a week after Anthony has claimed her daughter disappeared.
Since their investigation was launched on July 15, some Orange County sheriff's department officers have become well acquainted with the frustrations of following leads based on incomplete information, half-truths and many accidental, and some deliberate, lies.
In the original version of events, Caylee's mother reported her missing to police, saying she had dropped the child off at a babysitter's house on June 9. When she went to pick the child up, both the child and the babysitter had disappeared.
Casey's parents both corroborated the story until the hearing today, when Cindy Anthony said that the last time she saw the child was not on June 9, but on June 15, and that she had just been confused.
When police questioned Casey Anthony about her daughter prior to her arrest, they say Anthony misled them multiple times.
When she took police to the apartment where she said the babysitter, Zenaida Fernandez-Gonzalez, lived, they found that no one had lived in the apartment for five months. Though police have been working to track Fernandez-Gonzalez down, efforts have proved fruitless so far.
"I am not disregarding that this person may or may not exist," Mellich said during his testimony. "But Casey Anthony's friends and family have never met this person."
Casey also claimed to have worked for Universal Studios, but admitted later that that was not true.
But what unsettles Orange County Deputy Sheriff Carlos Padilla more than Anthony's imprecise information is her overall attitude.
"She has shown no emotion," Padilla told ABCNews. "That's unusual. At the time of the interviews ... she didn't seem concerned and that made this case much stranger."
"She spoke to deputies like she was talking about baseball. How do you get through to someone like that?" he added.
But with a homicide trial possibly brewing on the horizon, and the results of DNA tests on the newfound hairs pending, the Anthony family has not given up hope.
"I don't sleep, so I don't know what day it is. It's all one day," Cindy Anthony said in court today. "I am prepared to do anything I can to find Caylee."