Sweat claimed the lovestruck sewing-shop supervisor, who is charged with smuggling tools to the convicted killers, was the only other person who knew of their elaborate breakout plan, sources said on Monday.

Sweat — who a source said was "spilling his guts" to investigators — said he and Matt planned to drive to Mexico in Mitchell's car following their June 6 escape.

He said Matt, who had the words "Mexico Forever" tattooed on his back, came up with the idea of heading south of the border, boasting of connections he made while serving time for a fatal stabbing there, sources said.

"They would kill Mitchell's husband and then get in the car and drive to Mexico on the theory that Mitchell was in love with one or both of them," Gov. Andrew Cuomo said.