A rapist who attacked two women in the 1980s was caught more than 30 years later because he urinated in a neighbour's plant pot, police said.
Eric McKenna, 60, has been jailed for 23 years for raping women in Gateshead and Newcastle in separate street attacks, Northumbria Police said.
He picked on them when they were walking alone and on each occasion he grabbed them from behind and threatened to use a knife.
His crimes went undetected until 2016 when he was arrested following a neighbour dispute and DNA swabs were taken which eventually matched him to the unsolved attacks.
The first took place in April 1983 when McKenna raped a 21-year-old woman as she walked home near to the High Level Bridge in Gateshead.
The victim reported her ordeal to the police but officers could not identify her attacker.
Five years later he struck again in the Manors area of Newcastle and the second victim told police but they did not link the crimes and McKenna was not identified.
But in 2016, Northumbria Police neighbourhood officers arrested him for urinating in a neighbour's plant pot following a dispute and he was cautioned for harassment.
His DNA was processed and exact matches were made for the two historic rapes.
McKenna, of Clarewood Court, Newcastle, "did not flinch" when he was challenged over the rapes, Detective Constable Mick Wilson said.
McKenna was jailed after a trial at Newcastle Crown Court.
The detective said: "This is a very unusual case that stretches back more than 30 years but I am delighted to be stood here today knowing that this man is now behind bars.
"In the 1980s we did not have the same forensic techniques available that we do now and we have secured a conviction thanks to those developments.
"McKenna thought he had got away with his crimes but a neighbourly dispute and a moment of stupidity has landed him in prison for 23 years."