Search for Escaped New York Prison Inmates Expands to Vermont

The convicts thought New York's manhunt "might be hot," investigators said.

"Although we don't know where they are ... the destination they might have indicated is the state of Vermont," Shumlin said.

"They thought that New York was going to be hot, Vermont would be cooler in terms of law enforcement, and a camp in Vermont may be a better place to be," he said.

The clue about Vermont came as part of the investigation, and it is not clear if it came as a result of the interviews with employees at the prison or if it was one of the tips that was called in.

New York State Police Superintendent Joseph D'Amico said that they have received more than 500 tips today alone and they are following up on all of them. Corrections officers, other inmates and contract employees who worked at the prisons are among those being interviewed by investigators, and D'Amico confirmed that training supervisor Joyce Mitchell was among the interviewees.

"She befriended the inmates and she may have had some role in assisting them but I'm not going to go into any further details," D'Amico said.

According to two sources briefed on the probe, Mitchell, who has not been charged, is cooperating with investigators.

Authorities are investigating whether she played a role in the escapees getting the tools that they used to break out of prison, the sources said.

Cuomo said that "it's very possible" the escapees "had a several-hour head start on us" making the potential search area relatively widespread.

“I am confident we will find them. The only question is when,” he said.

New York State is offering a $100,000 reward for information leading to the apprehension and arrest of Matt and Sweat.

Using power tools, Sweat, 34, and Matt, 48, escaped the prison by cutting through a steel wall and breaking down bricks. They crawled through a steam pipe until reaching a manhole in the street outside the facility, authorities said.

Get real-time updates as this story unfolds. To start, just "star" this story in ABC News' phone app. Download ABC News for iPhone here or ABC News for Android here.