A retired policeman was murdered on a towpath by a boater after he was spotted putting a ticket on a boat that didn't have a mooring licence.
Daniel Wisniewski took exception when he saw former policeman Clive Porter placing a penalty ticket on someone else's narrowboat because it did not have a mooring licence.
The jury heard that 63-year-old Mr Porter was using his retirement from Hertfordshire Police to patrol the Grand Union Canal on behalf of the Canal and Rivers Trust and pick up any boats which were being used without licences.
The 46-year-old defendant was on his own narrowboat The Captain Golden Heart at a lock on the canal when he spotted Mr Porter posting a notice on the nearby Frosty Jack boat.
The jury at Reading Crown Court, where Wisniewski has been on trial accused of murder for three weeks, heard that after a verbal confrontation between Mr Porter and Wisniewski, the latter battered him to death, leaving him face-down in a water-filled ditch on the canal bank in Aylesbury.
Paramedics managed to pull him out of the water and worked desperately to save the 63-year-old's life.
However, he was declared dead soon after.
Prosecuting, Alan Kent QC said during the trial: "It is quite plain that shortly after killing Mr Porter, this defendant did not hang around, he fled the scene. He was eventually arrested about 12 hours later, at 12.30am on Tuesday, April 27.
"He was arrested after he hid under a trailer on a bit of land that his partner owned. He did not want to be found, he did not expect the police to find him, but they did."
The Polish national, who sat in the dock listening to an interpreter throughout proceedings, denied that he murdered Mr Porter, instead claiming that he tried to save him after he was attacked by a pair of unknown men who came from the Frosty Jack.
Mr Kent said: "He claimed that he was such a hero that he should get a medal from the Queen. There were not two men who attacked Mr Porter, it was Wisniewski."
The jury returned its verdict today, unanimously convicting Wisniewski of one count of murder just over six hours after retiring to consider the evidence.
In a tribute to Mr Porter, Hertfordshire Chief Constable Charlie Hall said: "We were incredibly saddened to hear of the tragic passing of retired police officer Clive Porter and our thoughts are with his family at this devastating time as they try to process an unimaginable loss.
"We would like to publicly recognise Clive for his unwavering dedication to policing. He displayed all the qualities of a truly good police officer and he will be remembered as an inspiration to us all. Thank you, Clive."
Wisniewski, of Wharf Road, Birmingham, is set to return to Reading Crown Court on Wednesday where he is expected to be sentenced to mandatory life in jail.
High Court judge Mr Justice Turner will set a tariff for when parole can be considered.
