DANNEMORA, NY — (CNN) His wife is accused of helping two convicted murderers break out of a New York prison. And the escape plan, a source says, also included a plot to kill him.

But how much did Lyle Mitchell know?

That’s one of the multitude of questions investigators are asking as they search for the two fugitives, Richard Matt and David Sweat, in a massive manhunt that was expanding Wednesday.

A source with direct knowledge of the investigation told CNN that prison tailor shop instructor Joyce Mitchell knew the two inmates had plotted to kill her husband, told him about their plans to break out of the facility and warned him that his life could be in danger.

But a lawyer representing Lyle Mitchell said the husband, who also worked in the prison’s tailoring block, was kept in the dark.

“He didn’t know anything about the escape plan,” attorney Peter Dumas said.

At this point, investigators don’t believe Lyle Mitchell was involved in plotting the escape, the source with direct knowledge of the investigation said.

On Tuesday, Lyle Mitchell was face to face with his wife for the first time since her arrest last week. She’s accused of sneaking hacksaw blades, chisels, drill bits, a punch and other contraband into the convicts’ hands before they broke out.

The couple spent an hour together and were separated by glass, speaking over a phone in a private, unmonitored conversation, Clinton County Sheriff David Favro said.

Lyle Mitchell was supportive, and his wife seemed comforted by his visit — the first she’d had since her arrest, the sheriff said.

“He’s providing support,” Dumas said. “He’s not planning to testify on her behalf.”

Joyce Mitchell’s attorney, Stephen Johnston, said he did not know what the two talked about. He described his client’s state of mind as “distraught, very weepy and very upset.”

Dumas said Lyle Mitchell is also struggling to deal with what’s happened and the revelation that “possibly there was a plan to do some harm to him.”

“He’s very confused. It’s just a lot that’s been thrown on his plate right now,” Dumas said. “He’s kind of reeling.”

Clinton County District Attorney Andrew Wylie has not commented much on the husband, other than to say he’s under investigation.

Investigators are looking at other prison employees as well and haven’t ruled out that they may have played a role in the escape, the source with knowledge of the investigation said.

Officials are also investigating whether other inmates might have helped create some type of diversion before, during or after Matt and Sweat escaped, the source said.

Joyce Mitchell has pleaded not guilty to the two charges brought against her and has been talking to authorities. If convicted, she could face up to eight years behind bars.

Authorities are investigating whether the two inmates threatened Mitchell to force her to help, a New York state official briefed on the investigation told CNN. Investigators say they think Mitchell began getting cold feet about executing the plan but possibly had agreed to supply a getaway car because of threats to her and her husband, the official said.

But her relationship with the prisoners was years in the making, authorities said.

She’d been investigated in the past for an inappropriate relationship with Sweat that led corrections officials to move him out of the tailor shop in 2013 and keep them separated, said Wylie, the district attorney.

That’s the year when she started having a sexual relationship with Matt, the source said.

The sexual relationship took place at the tailor shop in the Clinton Correctional Facility, the only known place the two were together, the source said.

With few clues pointing toward where Matt and Sweat went after they escaped, investigators are changing tack.

The search stretched into day 12 on Wednesday. The area that hundreds of law enforcement officers are combing is expanding, New York State Police said Tuesday evening.

Teams will be redeployed to new areas near the prison in Dannemora, New York, police said, saying the shifting search zone was based on information uncovered in the hunt for the fugitives.

“They’ve covered all the square footage over 10,000 acres, and covered it very well, so that we’re confident that that area is cleared, and we’re going to be moving on into a couple other areas that are fairly close to that search area just in case they are still here on foot,” Favro, the Clinton County sheriff, told CNN’s “New Day” on Wednesday.

More than 800 local, state and federal officers have been combing the dense woods and small towns in the area. Canine units are still searching for a scent that might lead police to Matt and Sweat, who escaped from the maximum-security facility known as “Little Siberia” in upstate New York on June 6.

“We’re putting our heart and soul into this,” Favro said of the search. “I’m confident that we’ll be able to get these two.”

But after earlier promising leads went cold, officials aren’t even sure they’re looking in the right place.

The fugitives could have made it across Lake Champlain to Vermont, and New York Gov. Andrew Cuomo has said he talked to his counterpart there to thrash out a “cooperative agreement” for the search.

Another possibility is Canada, whose border lies just 20 miles north of the prison.

But Jonathan Gilliam, a former FBI agent who has led manhunts, says the killers wouldn’t try to drive past border checkpoints — and going on foot through the thick woods is even harder.

“It’s kind of a harsh environment, cold at night,” he told CNN. “They’re instantly setting themselves up for a fall.”

Searchers are scouring parts of the Adirondacks in upstate New York, a 6 million-acre wilderness at the doorstep of the prison. It’s filled with hundreds of cabins, many of them abandoned in the off-season.

Investigators think Matt and Sweat could be holed up in one of them. Or, they warn, the pair could invade a home and take hostages.

But Gilliam says that would be “a big chance to take.”

“If you do that, even if you leave, now you’ve set a footprint for the police to latch onto,” he said.

According to authorities, Joyce Mitchell says Matt and Sweat told her they planned to drive to an unspecified destination about seven hours away.

She backed out of the getaway plan, and it’s unclear what other options the killers had in mind. But driving for that length of time at an average speed of 60 mph would put big cities like Boston, New York and Philadelphia within reach.

Those environments might be easier ones in which to disappear.

“People are very aware of who’s around them” in small towns, said Gilliam. “They’re very aware of what other people are doing. Once you get into a larger city, people just stop paying attention.”

Even farther afield is Mexico, a possibility that Cuomo mentioned over the weekend.

The country, about 2,000 miles away, features in Matt’s past.

In 1997, he murdered a man near Buffalo, New York, and then fled to Mexico, where he killed another man before being captured.

He had “Mexico Forever” tattooed on his back, police say.

Authorities are offering a $100,000 reward for information leading to the escaped inmates’ arrests.

It’s not clear how much money has been spent, but judging from the boots on the ground, it can’t be cheap.

New York State Police say 1,200 leads have developed, but so far it’s not clear whether any of them will pan out.

And time may be increasingly on the killers’ side.

“You can’t sustain this type of a manhunt for very long,” Gilliam said. “It’s just too much of a vacuum of all other resources.”

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