ATLANTA — A state investigation released Tuesday showed rampant, systematic cheating on test scores in this city’s long-troubled public schools, ending two years of increasing skepticism over remarkable improvements touted by school leaders.

The results of the investigation, made public by Gov. Nathan Deal, showed that the cheating occurred at 44 schools and involved at least 178 teachers and principals, almost half of whom have confessed, the governor said.

A culture of fear, intimidation and retaliation existed in the district, which led to a conspiracy of silence, he said in a prepared statement. “There will be consequences,” Mr. Deal said.

That will certainly include dismissals, according to school board members and the interim superintendent, Erroll B. Davis Jr., and could possibly result in criminal charges.