The manhunt for two escaped killers expanded to campsites and boat slips in Vermont on Wednesday, and State Police said a female prison staff member being questioned may have had a role in helping the men.

At a news conference outside the maximum-security prison, New York Gov. Andrew Cuomo and Vermont Gov. Peter Shumlin said investigators learned that the inmates had talked before last weekend's breakout about going to neighboring Vermont.

"New York was going to be hot. Vermont would be cooler, in terms of law enforcement," Shumlin said on Day 5 of the search. He and other officials would not say how authorities learned that information.

New York State Police Superintendent Joseph D'Amico also said that a prison employee -- identified in news reports as Joyce Mitchell, a training supervisor at the prison tailor shop -- had befriended the killers and "may have had some role in assisting them."

He would not elaborate.

Mitchell's son, Tobey Mitchell, 21, told NBC that his mother checked herself into a hospital with chest pains Saturday. He said she wouldn't have helped the inmates escape.

Using power tools, David Sweat, 34, and Richard Matt, 48, cut through a steel wall, broke through bricks and crawled through a steam pipe before emerging through a manhole in the street outside the 3,000-inmate Clinton Correctional Facility in far northern New York, about 20 miles from the Canadian border.

The breakout was discovered early Saturday, meaning the inmates may have had a head start of several hours, Cuomo said.

Authorities suspect they had help from the inside in obtaining the power tools. Unions representing guards and civilian staff at the prison said many have been questioned by investigators, but no one has been suspended, disciplined or charged.

Vermont authorities are patrolling Lake Champlain and areas alongside it, Shumlin said. Cuomo urged the people of Vermont to be on the alert and report anything suspicious, warning: "Trust me, these men are nothing to be trifled with."

As part of the search, state troopers and corrections officers in helmets and body armor also retraced their steps around the prison, checking garage doors, sheds, windows and other structures for signs of a break-in or other clues.

More than 450 federal and state law enforcement officers were taking part in the search, including customs agents, federal marshals and park rangers.

But at the late-afternoon news conference, D'Amico confessed: "I have no information on where they are or what they're doing, to be honest with you."

The killers' mugshots have been put on more than 50 digital billboards in New York, New Jersey, Massachusetts and Pennsylvania, according to State Police, and a $100,000 reward has been posted.

Law enforcement officials again asked the public to report anything out of the ordinary.

"We don't want them out searching the woods," Sheriff David Favro said. "But if you're sitting on your porch, get your binoculars out and see if you see something unusual."

In Dannemora, Barbara McCasland said officers asked to search her home but she told them no. "I'm pretty battened down here. My windows are locked and everything," she said.

As the manhunt dragged on, she said she was getting worried: "I wasn't in the beginning, but seeing that they've been out there so long, I am a little nervous."

Many in the prison town greeted the return of the searchers with a shrug. Many suspect Sweat and Matt are long gone and they are past any danger.

"I'm not worried about it," Jackie Trombley said. Referring to the searchers swarming the area, she said: "We've got these guys down the road. They're everywhere, so it really doesn't bother me."

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Virtanen reported from Albany, New York.