The first prison break in the 150-year history of the maximum-security Clinton Correctional Facility was described by New York Gov. Andrew Cuomo as a “sophisticated plan” that required power tools and “several days” to execute.

David Sweat, 34, who killed a sheriff’s deputy in 2002, and Richard Matt, 48, who kidnapped a man, beat him to death and dismembered him in 1997, could be “literally anywhere across the state” or in Canada, Cuomo said Sunday. Hundreds of law enforcement officials have set up a dragnet across the state to hunt for them.

According to authorities, here’s how the two convicted murderers made the brazen escape over the weekend from the facility in Dannemora, N.Y., about 20 miles south of the U.S.-Canada border:

The two inmates, who were in side-by-side cells, each cut a hole in the steel plates of the wall at the back of their cells, behind their beds, and climbed out. They both placed “dummies” made of various items in their possession that made it look like they were sleeping with hoodies on when guards walked by to do their visual checks of the inmates overnight.

Once outside the cell, the prisoners were on a catwalk about six stories high, according to officials. They believe the inmates climbed down, carrying power tools, and made it to a system of tunnels and pipes below.

At one point, the men cut open a 24-inch steel steam pipe and climbed in.

The two men even left a taunting note for authorities to find with the message “Have a nice day.” They wriggled through the pipe for a “fairly significant distance,” Cuomo said, before cutting their way out of the pipe on the other end.

The inmates also had to break through a brick wall, and officials told Cuomo they probably were able to “chisel out the blocks.”

They eventually ended up at a secured manhole cover outside the prison, where, officials say, they had to cut through a steel lock and chain from the inside before escaping to the street.

It is unclear how the inmates would have obtained power tools. Officials have said that all of the facility’s tools and equipment have been accounted for in an inventory check, but that investigators are interviewing contractors working at the prison to determine whether Matt and Sweat were able to acquire the tools from one of them.