AFP, NEW YORK: A frantic manhunt was on Sunday for two convicted murderers who busted out of New York state's biggest maximum security prison by cutting through cell walls with power tools and escaping along tunnels. Killers Richard Matt, 48, and David Sweat, 34, sneaked out of the all-male Clinton Correctional Facility in Dannemora sometime between Friday night and early Saturday, with police saying the discovery was made during morning "roll call" and warning the duo should not be approached. They reportedly left a taunting note behind saying: "Have A Nice Day." New York Governor Andrew Cuomo said on Twitter he had toured the daring route the pair took to freedom, posting images of the path the men were believed to have cut to escape. The pair used power tools to drill through walls and pipes, he said, and left sweatshirts and other clothing in their beds as decoys to make it appear they were still in their cells.