A man who killed his parents when an argument "got out of hand" was found hiding in a loft with blood on his hands, the Old Bailey has heard.
Daniel Dighton, 35, was discovered behind a chimney stack in blood-stained jeans at the family home in south Croydon, south London.
Police followed a trail of blood from the bodies of Barry and Elizabeth Dighton to stairs leading to the loft.
Dighton has admitted killing the couple but denies murder.
Mrs Dighton, 60, was stabbed more than 20 times and her 61-year-old husband suffered four stab wounds in the attack in September 2009.
'Blood on hands'
Police called to the house in Campden Road by concerned neighbours found the couple covered in blood in the living room.
Pc Mark Goodson told the court he then heard a noise and followed a trail of blood to the loft where he found Dighton.
He said: "It made me jump. I told him to come out and show his hands. I could see he had blood on his hands."
A carrier bag with two knives were found in a bedroom.
Pc Michael Matthews said Dighton told him: "It's just an argument that got out of hand.
"I don't normally lose my rag like that."
The officer said: "His voice appeared that of a child who had done something wrong. It was a soft voice. I could see water in his eyes."
Jurors have heard that the Dightons returned home at lunchtime from a shopping trip "to find their layabout of a son still in bed and hungover".
Crispin Aylett, QC, prosecuting, said a "routine" quarrel broke out and quickly got out of hand.
He said: "The defendant armed himself with two knives, stabbing both of his parents to death in an attack of terrible ferocity."
The case continues.