New information is coming out today about how convicted killers Richard Matt and David Sweat escaped from a New York state prison last month. 

Officials say Sweat - who was captured Sunday after being shot twice - has told them that the pair actually escaped the prison the night before their breakout.

Clinton County District Attorney Andrew Wylie said that Sweat began working on the plan in January and that a "dry run" was conducted June 5. 

AP reported:

The men poked their heads out of a manhole but decided it was too close to nearby homes, Wylie said. The next day, they exited the tunnel through a manhole that was slightly more isolated despite being located in the middle of an intersection just a block from the prison walls, he said. The second manhole can be seen from a window in the prison tailor shop where the two convicts worked.

 

It was previously reported that Matt and Sweat used power tools to cut a hole in their cell wall and a 24-inch steam pipe that they crawled through.

 

But Sweat, who claimed to police that he was the mastermind of the plan and did all the work, said they only used a hacksaw blade, according to Wylie.

He said Sweat was able to gain access to the interior tunnels between 11:30pm and 5:00am in the days before the escape to finalize the plan. 

From AP:

Authorities said the two reached the tunnels via an interior catwalk — narrow utility corridors between cellblocks providing access to the bowels of the prison — they were given access to by a corrections officer who has since been charged in connection with the escape.

"He said he had been out in the catwalk area for a couple of weeks" before the breakout, Wylie said.

Gretchen Carlson went over the latest developments this afternoon with former D.C. homicide detective Rod Wheeler and Press-Republican reporter Joe LoTemplio.

Wheeler said the "startling" part is that the planning began around six months ago and it appears that Sweat was able to "recruit" prison workers into the plan.

"That institution has some huge problems to correct," he said. 

Watch the report above.