Video shows escaped killer joking about dipping darts in 'AIDS blood'

A video of one of the killers on the run from a New York jail has emerged showing him joking about creating an "AIDS weapon" with a blowgun.

Richard Matt, who escaped with fellow killer David Sweat from Clinton jail on June 6, is seen in the footage showing off the weapon, ABC News has reported.

The video was shot back in 1997, just months before Matt, 48, murdered and dismembered a former employer.

The unknown man holding the camera introduces Matt, dressed in a grey shirt, white pants and suspenders, as "my friend Ricky Matt ... a freaking crazy lunatic maniac".

Matt holds up the blowgun for the camera.

Later, the cameraman shoots a dart into Matt's arm, but the then-30-year-old appears unworried.

"Let’s dip these in AIDS blood, and we’ll put a patent on them and sell as deadly weapons," he tells the camera.

Matt and Sweat have been on the run for the past few weeks despite police converging on locations of suspected sightings on a number of occasions.

Their prison-issue underwear was recently found in a hunting cabin.

Prison guard Joyce Mitchell is alleged to have helped the pair escape jail.