A man killed his gay partner at their boat home on the River Medway and then attempted to stage a cover-up, a court heard.
Kenneth Harman claimed he had returned to The Impulse at Medway Wharf Road, Tonbridge, and found Michael Castle dead.
But Harman, 55, had inflicted a fatal single stab wound to 61-year-old Mr Castle’s chest after the pair rowed, it was alleged.
Maidstone Crown Court heard the couple had been living on the boat for two or three years and were both heavy drinkers.
Jonathan Higgs, prosecuting, said on the day of the murder on February 15 a friend, Paul Kinsey, and his son went to the boat to fix the starter motor.
While there, another friend, Danny Draine, turned up. While they were there, Harman and Mr Castle argued.
Mr Kinsey and his son left and while Mr Draine remained, Harman and Mr Castle fell out again. They rowed about a radio and Mr Castle threw it into the river.
"It was pretty clear to Mr Draine that things were getting pretty heated," said Mr Higgs. "He left shortly after that. He did not see Mr Castle again."
CCTV cameras on a Lloyds building filmed Mr Draine walking along a tow path just after 2.30pm.
Harman telephoned police at 2.54pm and told how he had returned to the boat after being away for 45 minutes to find his mate dead.
Officers and paramedics arrived at the scene to find Harman standing on the river bank with a drink in his hand. They went onto the boat and found the body.
Harman said he had been into town to get some trousers from a charity shop. He had blood on his hands, he said, from checking to see if Mr Castle was dead.
Harman, who denies murder, was at first treated as a witness, but then became a suspect. CCTV did not show him walking on the tow path that day.
The prosecutor said Harman phoned Mr Kinsey 12 minutes before alerting the emergency services and told him: "I have just come home and found my partner dead."
Mr Higgs said: "The Crown say this was somebody in panic mode. He must have already stabbed his partner by the time he called Mr Kinsey.
"When it has ended, he still doesn’t know how to cover his tracks. He phones the emergency services and puts on a show for them about how he found his partner dead."
The jury of seven women and five men was due to visit the site of the murder on Tuesday morning.
The trial continues.