DANNEMORA, N.Y. » By the time David Sweat and Richard W. Matt engineered their extraordinary escape from the maximum-security prison here, corrections officers were rarely shining lights over the faces of inmates during hourly bed checks, making it hard to know if a living, breathing person was inside a cell.

The catwalks and underground tunnels that made their getaway possible were no longer being inspected regularly.

And no one was inside two of the 35-foot-high guard towers when the two convicted killers climbed out of a manhole outside the prison walls and fled into the night.

No single lapse or mistake in security enabled the two men to break out of the Clinton Correctional Facility here, long considered one of the most secure prisons in the nation. But it now appears that an array of oversights, years in the making, set the stage for the prison break a little over two weeks ago and for the ensuing manhunt, which this weekend zeroed in on a possible sighting of the men in the town of Friendship, New York, more than 350 miles southwest of the prison, even as the State Police said the focus of the search would remain around Dannemora.

At Clinton, a sense of complacency had taken hold, current and retired corrections officers said. In some ways complacency might have been understandable. There had not been an escape from the 170-year-old prison in decades, and officials say no one had ever broken out of the maximum-security section.

"As the months go by, years go by, things get less strict," said Keith Provost, a retired corrections officer who had worked at the prison for more than 15 years.

Some security posts were no longer filled, despite modest increases in personnel over the past decade.

Linda Foglia, a spokeswoman for the state Department of Corrections and Community Supervision, said in a statement that three agencies – the New York inspector general’s office, the Clinton County district attorney’s office and the State Police – were conducting "top-to-bottom" independent investigations of security practices at the prison.

"The various investigations will determine what, if any, lapses occurred, and at that point, all appropriate action will be taken and corrective reforms will be instituted," Foglia said in the statement.

Much remains unknown, not the least of which is the whereabouts of Matt and Sweat, whose escape has touched off a huge manhunt involving hundreds of law enforcement officials following leads starting in this small village in the North Country, stretching to the borders of Canada and Mexico, and on Saturday reaching, Friendship, in New York’s Allegany County.

Officials now say that Sweat and Matt likely had significant help from several people, including a civilian employee, Joyce E. Mitchell, who has been arrested, and as many as four corrections officers who are under investigation. One officer, Gene Palmer, has been placed on administrative leave.

What has received less attention are the internal failings at the prison that enabled their escape.

Routine Lapses

Prison rules forbid putting sheets across cell bars to obstruct viewing, except when an inmate is using the toilet. But in practice, officers said, inmates frequently were allowed to hang sheets for lengthy periods.

And unlike many prisons and jails across the country, the Clinton prison does not have video cameras on the cellblocks to detect suspicious activity, several current and former officials say.

Several officials, including the Clinton County district attorney, Andrew Wylie, now say there is a good chance that Matt and Sweat had been at work on their plan for weeks, maybe months. Night after night, the authorities have come to believe, the two men stuffed their beds with crude dummies, slipped out of holes they had cut in the back of their cells and climbed down five stories using the piping along the walls. They then set to work inside the tunnels under the prison, spending hours preparing their path of escape before returning to their cells unobserved.

A major failing, it seems, was the nightly bed checks. Officers are supposed to make rounds every hour from midnight to 5:30 a.m. Corrections department rules say that officers must be able to see the inmate’s skin and detect breathing. But through the years, the inmates have been permitted to completely cover themselves with blankets, wear hooded sweatshirts over their heads and put pillows over their faces, according to current and former officers.

As a result of complaints by inmates about being awakened, guards no longer shined flashlights in their faces, and typically pointed the beam only to the shoulders.

"A lot of times, like every other job, you get complacent and when you see a lump in a bed, you’re good to go," said Mark Siskavich, a retired corrections officer who last worked at the prison in 2012.

Gathering Tools

At the time of the escape, Sweat and Matt were housed in the honor block, a reward for good behavior, in Cells 22 and 23 on the top tier, four stories up from the cellblock floor, which is known as the flats. They would put their dummies in place and climb out of two square openings cut into the back of their cells. Wylie said that it appeared Matt cut through his cell first, likely using a hacksaw blade smuggled to him by Mitchell, the civilian employee who is under arrest.

The steel wall at the back of the cell was only about a quarter-inch wide, no thicker than a cellphone, Wylie said. He said it appears that the hole in Sweat’s cell was cut with a power tool that may have been left on a catwalk that runs behind the cell.

The inmates may have also found other tools left by contractors on the catwalk. At one time, corrections officers regularly patrolled the catwalks, listening in on inmates’ conversations and gathering intelligence. But in recent years, according to several current and former officers, including Siskavich and Provost, officers rarely if ever went back there.

Once Sweat and Matt were out of their cells, they used pipes running vertically and horizontally along the wall behind the cellblock to climb down the four flights through a gap between the catwalks and the wall, Wylie said.

From there, they would have been able to enter a system of tunnels underneath the prison that are wide and high enough for an adult to easily pass through. They then broke through a brick wall and at some point identified a large steam pipe running under the prison that they would eventually use to make their escape.

The more authorities have looked into the case, the more they have been struck by the deep knowledge the inmates seemed to have of both the details of the prison’s construction and the gaps in its security.

There is an extensive network of tunnels running in all directions, but the authorities said there is no evidence that they had considered using any other route besides the one they chose.

Wylie said the tailor shop where they worked had a view over the prison wall, which could have given them "the lay of the land," including the location of the prison’s power plant several blocks away that the steam pipe they used would have connected to.

During the months the prison was still being heated, the steam pipe would have made the tunnels too hot to work in. That could mean that they waited until May, when the heat was shut off for the season, to access the tunnels, officials said.

The tunnels are far away enough from the cellblocks and deep enough underground that power tools could have been used without being heard, said Gary Amell, a retired warden who was an officer at the prison in the 1980s.

In the past, the tunnels were inspected once a week, he said. When he used to do the inspections, he recalled it would take him an entire day.

Those tunnels have not been inspected regularly in recent years, according to current and former corrections officers. One current officer who declined to give his name because supervisors told him not to speak with the press, said the last inspection he could recall was in October.

Among the many unanswered questions is how they got out of the steam pipe. Wylie said there was a second hole cut at the point of escape.

The manhole was closest to the two 35-foot watch towers on the south side of the prison known as 1 Post and 2 Post. For years now, they have not been staffed overnight.

Several corrections officials noted that there is no direct line of sight from the towers to the manhole. However, one officer who has worked in the towers said that it was likely that movement there would have been detected.

Either way, since the escape, the towers have been staffed around the clock.

At about 12:30 a.m., Leslie Lewis, 29, who grew up in Dannemora, said he saw two men in his backyard not far from the manhole cover. One of the men he described as heavyset with dark skin, the other thinner with light skin. Lewis said in an interview that he yelled at them and asked what they were doing. He said the thinner one replied, "Oh, sorry, we’re on the wrong road; we didn’t know where we were going."

Both were wearing jeans, he said. The heavyset man was carrying a canvas bag, and the slimmer man, who was wearing a white T-shirt, had a black fabric guitar case, Lewis said.

Wylie confirmed that Sweat had kept a guitar in his cell and may have been carrying tools and clothes inside a fabric case that night.

The last Lewis said he saw of the two men they were hurrying down Barker Street. Then they disappeared.

Corrections officials said the two inmates were not discovered missing until the bed check at 5:30 a.m. June 6.

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