Authorities in the state of New York have intensified efforts to catch a second escaped murderer - after one of the men was killed in woods by a border patrol agent.
Richard Matt was tracked down to a remote cabin - 30 miles from the jail - but David Sweat is still on the run.
The pair used power tools to escape three weeks ago.
New York Governor Andrew Cuomo says police were alerted after a camper van was attacked:
The drama unfolded in the wilderness around Lake Titus.
Police helicopters were reported to be swarming around the search area near the Canadian border.
More than 1,100 law enforcement officers have been concentrating their search in the area.
Authorities said earlier on Friday that police had found more evidence left by the fugitives.
New York State Police Major Charles Guess said the items had been found on Thursday at a cabin and Friday morning in a field.
The discovery was made in the town of Malone, 10 miles north of Lake Titus.
Other evidence was found last weekend in a hunting cabin in the neighbouring town of Bellmont.
The duo left a note taunting guards as they busted out of maximum-security Clinton County Correctional facility in Dannemora.
The pair cut through a steel wall at the back of their cells, broke through a brick wall, and sliced through a chain and a lock on a manhole to escape the prison.
Sweat was serving a life sentence for killing a sheriff's deputy.
Matt was serving 25 years to life for the kidnap, torture and murder of his former boss.
