Who are US fugitives Richard Matt and David Sweat?

By Tim SwiftBBC News, Washington

Hundreds of police officers have been combing through the swamps and woods of rural New York state and Vermont looking for two violent criminals who made a elaborate prison escape. Richard Matt and David Sweat have been on the run for almost a week now. But who are the targets of this massive manhunt?

Richard Matt

Age: 48

Early life: He grew up in the small city of Tonawanda, New York, near Buffalo. Classmates told the Rochester Democrat and Chronicle that Matt was often in trouble as a child. "He would terrorise kids on the (school) bus," Randy Szukala told the newspaper. As a teenager, he ran away from home on a stolen horse. Eventually, Tonawanda police Capt Frederic Foels told the Democrat and Chronicle, he became a "small-time thug".

Previous crimes: Matt had been known to law enforcement for years, committing numerous offences, but his most serious crimes appear to have started in the late-1990s. In 1997, a fisherman found the dismembered body of William Rickerson, a Buffalo businessman, in the Niagara River. Investigators zeroed in on Matt - one of Rickerson's former employees. But Matt fled to Mexico before he could be arrested. While there, he reportedly killed an American man in a bar, landing him in a Mexican prison. He was eventually sent back to New York in 2007. Matt was convicted and sentenced to 25 years to life with no chance of parole before 2032.

Previous escapes: In 1986, Matt escaped from the Erie County Correction Facility. To escape, Matt sneaked past a guard and climbed a 9ft (2.7m) wall. The razor wire at the top of the wall scarred his hands. His son, Richard Harris, told theBuffalo News that his father showed off the scars, boasting of the escape attempt. Police found Matt five days later at his brother's house in Tonawanda. Mr Harris said that Matt also boasted of an escape attempt while in Mexico. He was shot in the shoulder during the attempt and proudly showed Harris and his mother the wound, the Buffalo News reported.

"Charmed": Despite the brutal nature of his crimes, some have described him as "handsome" in his early life and a ladies' man. Joyce Mitchell - a prison worker who police say helped in the most recent escape - told investigators that Matt "made her feel special" and that she was "charmed" by him. One former New York police officer compared him to cult leader Charles Manson.

Previous security measures: When he returned to New York in 2007, authorities exercised extreme caution. The New York Times reported that measures included staffing the courthouse with double the usual number of deputies and making Matt wear an electric stun belt.

Quote: "He is the most vicious, evil person I've ever come across in 38 years as a police officer." Gabriel DiBernardo, a retired captain with the North Tonawanda Police Department, told the New York Times.

David Sweat

Age: 34

Early life: His mother, Pamela Sweat, told the Press & Sun-Bulletin of Binghamton, New York that her son had a troubled childhood and had violent tendencies. "I don't want nothing to do with him," Ms Sweat told the newspaper. "He has tormented me since he was nine years old, and now he's 34 and I feel like he's still doing it."

Previous crimes: In 2002, a New York sheriff's deputy caught Sweat and his cousin, Jeffrey Nabinger, with stolen guns. But when the deputy, Kevin Tarsia, tried to arrest them, the pair shot Tarsia 15 times and ran him over with their car, theLos Angeles Times reported. He was later sentenced to life in prison without parole. Before his murder conviction, he had served two years in prison for attempted burglary, but was eventually paroled.

'Polite' letter: Julia Hunter - a reporter with the Press & Sun-Bulletin - wrote to Sweat in 2010, hoping for a jailhouse interview years after his conviction. She didn't get the interview but she did get a written response from Sweat. He wished Ms Hunter "good luck" on her new job and sympathised that she was probably under pressure from her editors. USA Today has published the letter in full.

Previous escapes: None