The grainy footage shows Matt -- nicknamed “Ricky” -- glaring into the camera as he poses with a blow dart gun.
An associate, who is off camera, can also be seen testing out the weapon on Matt’s body, shooting a blow dart into his arm.
The video was recorded before Matt was arrested for beating, torturing, killing and dismembering his former boss, William Rickerson.
Then 30, Matt would later be convicted and sentenced to 25 years to life.
Matt and another man, David Sweat, escaped from a New York prison on June 6. The search for the men has intensified west of the prison in recent days, after prison-issue underwear and other items were recovered at a hunting cabin.
Food collected from the site featured positive DNA samples from both suspects, an official briefed on the search said.
New York State is offering a $50,000 reward for information that leads to the capture of either man or $100,000 for both. The U.S. Marshals Service has placed Sweat and Matt on the 15 most wanted fugitives list and is offering a $25,000 reward.