An immigrant accused of strangling an elderly widow with a mower cord on an allotment has told jurors he went there that day to buy opium.
Iranian Rahim Mohammadi, 41, also said he heard shouting on the day 80-year-old Lea Adri-Soejoko was killed but thought it was just a drunken fight.
He is on trial at the Old Bailey accused of beating up her up at the Colindale allotments in north London, then throttling her to stop her reporting him.
Her body was found in a mower shed after she failed to turn up at a meeting on the evening of February 27 last year.
The prosecution alleges Mohammadi wanted Mrs Adri-Soejoko to retire as secretary of the allotments so he could take over.
Tensions had flared at an AGM four months before when Mrs Adri-Soejoko told him to "shut up" in a discussion over the enforcement of notices to leave.
He told her to "shut up" back and called her a "little witch" as he walked out, the court heard.
Giving evidence, Mohammadi said he was "embarrassed" about calling her names and later apologised to her over tea in his shed.
Describing the incident, he said: "Towards the end of the meeting I stand up and say, 'bye bye little witch' because she used to call me 'little puppy'.
"I wanted to apologise first because I was embarrassed really because I had said 'shut up' in front of a few people. It was not nice."
Tyrone Smith QC, defending, asked what their relationship was like afterwards.
The defendant said he was "embarrassed" but she told him to "forget it".
Two days before the killing, the defendant said he met a man on the allotment who offered to sell him £200 of opium for his bad back.
He arranged to see another associate to collect the remainder of the drugs on February 27, he said.
On the day of the killing, Mohammadi said he had gone to Mrs Adri-Soejoko's house to collect a key to the main gate.
She gave him coffee and asked his advice about carpeting her stairs because the boards were slippery, he said.
Later, he said he returned a tape measure to Mrs Adri-Soejoko.
During the day, the defendant said he made three trips away from the allotment to buy tobacco, water and opium and spent time watching YouTube videos at his shed.
He told jurors that when he left on his third trip, he heard someone shouting but carried on.
He said: "I just said to myself now they are drunk and they are fighting each other."
The court has heard how Kurdish Mohammadi sought political asylum in Britain in 2005 and was given indefinite leave to remain in 2010.
His association with the allotment began when he was referred there in 2008 by the Freedom from Torture charity.
Mohammadi, of Hackney, north-east London, denies murder.