Prosecutors in the Casey Anthony murder trial called witnesses Friday to bolster their contention that the woman's mother couldn't have been home to perform Internet searches for a harmful chemical.

Testimony by two of Cindy Anthony's co-workers _ among the last of the trial _ was intended to disprove her surprising assertion this week that she was the one who keyed in searches for the term "chloroform." Prosecutors have argued that Casey Anthony made the searches as she plotted to kill her 2-year-old daughter in 2008.

Prosecutors used parts of Friday and the previous day to give their rebuttal to the defense's case. Closing arguments are expected to take place Sunday, after which jury deliberations will begin.

Gentiva Health Services Chief Compliance Officer John Camperlengo answered questions about Cindy Anthony's work history on two days in March 2008 when the "chloroform" searches were done on a computer at the Anthony household. The company's electronic records show that she was logged into her company's system for most of the day on both March 17 and March 21.

Using the latter date as an example, Camperlengo said the system would not have recorded Anthony's presence if a person hadn't been actively using the work computer.

"Someone human was pushing the enter button to enter data," he said Friday.

Cindy Anthony's supervisor at Gentiva, Deborah Polisano, also testified that electronic work records show that Cindy Anthony was on the clock for 10 hours on March 17 and nine hours on March 21.

Earlier this week, Cindy Anthony testified that she had performed the Internet searches for "chloroform" while looking up information on chlorophyll, a green pigment found in plants. Chloroform, on the other hand, is a chemical that can be used as a sedative and is fatal to children in small doses.

She testified that she was home on the days when the computer searches were run. She said she could leave work when she wanted, and that the work records might not have reflected her absence.

Casey Anthony is charged with first-degree murder in the 2008 death of her 2-year-old daughter, Caylee. If convicted of that charge, she could face the death penalty. The prosecution contends she used duct tape to suffocate the toddler, while the defense says the girl accidentally drowned in her grandparents' above-ground swimming pool.

Also Friday, forensic anthropologist Michael Warren was called back to dispute a defense expert's claim that the medical examiner made a mistake by failing to saw open Caylee's skull to examine it. The defense has tried to cast doubt on the forensic evidence in the trial.

"No sir, there is no protocol that I'm aware of to do that," Warren said.

Both sides have Saturday off to settle on final instructions for the jury, and prepare their closing arguments.

Earlier Friday, lead defense attorney Jose Baez said prosecutors had failed to disclose all the information a computer expert and forensic anthropologist planned to testify about. Baez wanted the evidence and witnesses to be excluded, but Perry only gave him the option of taking their depositions.

He did, causing an unscheduled recess that lasted throughout the morning.

"Your honor, I will stay here and do the work, and stay here as long as it takes," Baez said.

While the defense rested Thursday, experts said defense attorneys may have left lingering questions and failed to deliver on promises they made at the outset to explain how the toddler died.

Casey Anthony did not take the stand, and the defense did not present concrete evidence that Caylee accidentally drowned.

Her attorneys also never produced any witnesses bolstering the claim made in opening statements that Anthony had acted without apparent remorse in the weeks after her daughter's death because she had been molested by her father as a child, resulting in emotional problems.

The prosecutors' case relied on circumstantial and forensic evidence, and it did have holes. They had no witnesses who saw the killing or saw Casey Anthony with her daughter's body. And there was no certain proof that the child suffocated.

The defense said in its opening statement that Caylee drowned and that her grandfather George Anthony, a former police officer, helped cover up the death by making it look like a homicide and dumping the body near their home, where it was found by a meter reader six months later. George Anthony has vehemently denied any involvement in Caylee's death, the disposal of her body or molesting his daughter, Casey.