ORLANDO – Internet searches for how to make chloroform and neck-breaking were done on a computer that a Florida mother accused of killing her 2-year-old daughter had access to, an expert who analyzed the machine testified Wednesday at the mother’s trial.

The queries were done several weeks before Caylee Anthony was last seen, though the expert could not say exactly who performed the searches.

Casey Anthony is charged with first-degree murder in the girl’s death, and prosecutors say she used duct tape to suffocate her daughter in summer 2008. The child’s remains were found about six months later.

Anthony’s defense attorney says the toddler accidently drowned in her grandparents’ swimming pool.

John Dennis Bradley, a former Canadian law enforcement officer who now develops software for computer investigations, analyzed a data file from a desktop seized from the home of George and Cindy Anthony, where Casey lived sometimes.

Bradley said he was able to use a program to recover deleted searches from March 17 and March 21, 2008. On March 21, someone searched the website Sci-spot.com for “chloroform” 84 times, he said.

“I believe some of these items might have been bookmarked,” Bradley said of the search results.

Under cross-examination, though, Bradley acknowledged there were two accounts on the desktop and there was no way to know who actually performed the searches.

“So what you’re saying is that there are limited things you can tell from this?” Anthony’s attorney Jose Baez said.

“Yes,” Bradley responded.

Baez also pointed out that several of the searches, including ones for “self-defense” and “household weapons” had no bearing on his client’s case.

Bradley was the one of three computer forensic witnesses to take the stand on the 13th day of the trial, which also included testimony from an officer whose K-9 signaled that there was a scent of human composition in the Anthonys’ backyard.

Sgt. Kristin Brewer testified that her K-9 partner, Bones, signaled decomposition in the backyard during a search in July 2008. Another police dog handler testified Tuesday that his K-9 partner also detected decomposition in the backyard, as well as in the trunk of Anthony’s car.

Neither K-9 partner was able to detect decomposition during a second visit to the Anthony home. When asked why, Brewer said that whatever had been in the yard was either moved or the odor dissipated.

Forensics scientists testified earlier this week that high levels of chloroform were found in Anthony’s car. Chloroform is a chemical that is associated with human decomposition, but the compound also can be used torender a person unconscious.