DANNEMORA, NY — (CNN) U.S. Marshals have added the convicted murderers who broke out of a maximum security prison in upstate New York to their 15 most wanted fugitives list and offered a $50,000 reward for information that leads to their capture.

The list “is reserved for the worst of the worst,” said U.S. Marshals Service Director Stacia Hylton. “There is no question David Sweat and Richard Matt fall into this category,” she said Thursday.

Now in its 14th day, the massive manhunt for the escaped inmates continues in the area of the Clinton Correctional Facility where state police have been checking seasonal camps and have cleared more than 160 abandoned buildings.

State police also asked hunters and homeowners with surveillance cameras to check their footage all the way back to June 6, the day of the prison break, for any unusual activity.

The search for Matt, 49, and Sweat, 35, has reached all the way to the borders Canada and Mexico, where wanted posters of the escaped killers are being handed out.

And as investigators widen their search for the fugitives, more details are emerging about the relationships between prison tailor shop instructor Joyce Mitchell and the escapees.

Her husband, meanwhile, feels betrayed by what happened, his attorney says.

Before he broke out of prison, Matt at one point made a painting for Mitchell, who is now accused of helping him and another inmate escape.

Using a photograph, Matt painted a picture of Mitchell’s children, Clinton County District Attorney Andrew Wylie told CNN.

And in April, Wylie said, Mitchell gave the painting to her husband as a wedding anniversary present. In exchange, Mitchell gave Matt a pair of speed bag gloves, similar to boxing gloves.

Authorities have also said Matt had a sexual relationship with Joyce Mitchell.

Mitchell, 51, is behind bars, accused of helping them break free and sneaking hacksaw blades, chisels, drill bits, a punch and other contraband into the convicts’ hands before they broke out.

No court date has been set for Mitchell, who has pleaded not guilty to the two charges brought against her and has been talking to authorities. If convicted, Mitchell could face up to eight years behind bars.

Mitchell’s husband, Lyle, also worked in the prison’s tailoring block.

But the prosecutor said Wednesday that Lyle Mitchell didn’t know about the prisoners’ escape plan before it happened and wasn’t aware of his wife’s relationships with the inmates.

After Matt and Sweat broke out, Wylie said, Joyce Mitchell warned her husband that the men were free and had been plotting to kill him.

“She advised him after the escape of what happened, including the possible murder plot,” Wylie said.

Joyce Mitchell’s attorney says that doesn’t mean she was participating in the plot.

“I don’t believe she was involved in any attempt to kill her husband,” her attorney, Stephen Johnston, told CNN. “Just because she heard something doesn’t mean she was going to act on it. … She did not want to be a part of it and did not.”

For his part, Lyle Mitchell feels betrayed, lost and is “looking for his life again,” according to his attorney.

He had no clue his wife was involved in the elaborate prison break when the two of them were first questioned by police, said his attorney Peter Dumas.

Only two days after the escape did Lyle Mitchell realize “that something is going on here,” and confront his wife, who warned him that the escaped men had been plotting to kill him, Dumas said.

The-CNN-Wire ™ & © 2015 Cable News Network, Inc., a Time Warner Company. All rights reserved. (PHOTO: NY State Police)