The two murderers who are on the run after an intricate escape from an upstate New York maximum security prison have a violent past: One of the men has killed twice and escaped from jail before, and the other killed a law enforcement officer.
"These are dangerous men," New York Gov. Andrew Cuomo said, adding that they are "capable of committing grave crimes once again."
Here is a closer look at the convicted killers who lived in adjacent cells at Dannemora's Clinton Correctional Facility:
RICHARD MATT, 48
Matt is from Tonawanda, New York, about 10 miles outside of Buffalo, and over 300 miles from Clinton.
Tonawanda Police Capt. Fredric Foels told ABC News today he dealt with Matt in the late-1980s and early 1990s.
"He was arrested about eight times in that stretch," he said.
Foels said they called him "Ricky Matt." Matt's alleged crimes at the time included assaults, possession of a weapon, possession of stolen property and harassment, Foels said.
Foels said he was just as surprised as everyone else to hear of Matt's escape.
"It was right out of a movie," Foels said. "I was just in awe. ... That the type of feat he was able to pull off. ... Hearing that name again after so long brought back that time we dealt with him in the late '80s."
But this wasn't the first jail break for Matt. In 1986, while Matt was serving one year for assault, he broke out of the Erie County jail, the Buffalo News reported. He was eventually caught and returned to prison, according to the New York Times.
In the 1990s, Matt then spent several years in prison for attempted burglary, according to the Associated Press. He was released in 1997.
But later that year, he was arrested for beating, torturing, killing and dismembering his former boss, William Rickerson, the AP reported.
Before his trial, Matt fled to Mexico, where he allegedly killed a man in a bar fight, the AP reported.
He was later extradited to the United States and convicted of Rickerson's death, according to the AP. Matt was sentenced to 25 years to life.
While incarcerated at Clinton, Matt had one blemish on his disciplinary record. In 2011, Matt was charged with smuggling, tattooing and providing false information, according to state records obtained by ABC News. He received 30 days of confinement in his cell and loss of recreation, phone and commissary privileges.
Matt, is described as standing 6 feet tall, weighing 210 pounds and having black hair and hazel eyes. He has tattoos reading "Mexico Forever" and a heart on his chest and left shoulder, police said.
DAVID SWEAT, 34
Sweat is from Dickinson, New York, about 50 miles west of Clinton.
He first went to prison when he was 18 for an attempted burglary, according to the AP.
In 2002, Sweat and two others had allegedly stolen guns when they were confronted by Broome County Sheriff's Deputy Kevin Tarsia, near the border of New York and Pennsylvania, the AP reported.
Tarsia was shot 15 times and run over. Sweat and another man then stole Tarsia's handgun and Tarsia was shot two more times, authorities said, the AP reported.
Sweat was sentenced to life in prison.
Sweat also had a disciplinary record at Clinton. In 2014, Sweat was charged with interference and harassment, according to state records. His punishment was suspended.
Sweat is described as standing 5 feet 11 inches tall, weighing 165 pounds and having brown hair and green eyes. He has tattoos on his left bicep and his right fingers, police said.
New York State is offering a $100,000 reward for information leading to their apprehension and arrest.
The Associated Press contributed to this report.