ORLANDO, Fla. – The Florida sheriff's office that investigated the disappearance of Casey Anthony's 2-year-old daughter overlooked evidence that someone in their home did a Google search for "fool-proof" suffocation methods on the day the girl was last seen alive.

Orange County sheriff's Capt. Angelo Nieves said Sunday that the office's computer investigator missed the June 16, 2008, search. The agency's admission was first reported by Orlando TV station WKMG. It's not known who performed the search. The station reported it was done on a browser primarily used by the 2-year-old's mother, Casey Anthony, who was acquitted of the girl's murder in 2011.

Anthony's attorneys argued during trial that Casey Anthony helped her father, George Anthony, cover up the girl's drowning in the family pool.