A file photo of a young Adam Lanza.

Hartford, Connecticut - Connecticut's chief medical examiner says he doubts genetic analysis of the body of the gunman who fatally shot 20 children and six adults at a school last month will explain his actions.

Dr. H. Wayne Carver II autopsied the body of the gunman Adam Lanza and said an examination of Lanza's brain showed nothing unusual.

Carver told The Hearst Connecticut Media Group that the testing was a “fishing expedition.”

Carver said Lanza's brain showed no tumor or gross deformity, though he didn't expect to find one.

“That would be associated with very severe disabilities,” he said.

A toxicology exam, which could take several weeks, involves testing body fluids for psychiatric medications or illegal substances. Carver said the result could provide “potentially valuable information” in creating a full picture of Lanza.

The 20-year-old Lanza fatally shot himself after the December 14 attack.

Lanza's body was claimed by his father on Dec. 27, and the public may never know what happened with the remains. - Sapa-AP