A teenager told a mum-of-three "hope you have a nice night" hours before he planned to kill her and her husband, a court has heard.
Shaun Skarnes, 19, and Christopher Monks also "laughed" as they discussed whether to throttle or smother Monks' adoptive parents, Christopher and Elizabeth, while playing computer games in Monks' home in Clayton-le-Woods, Preston Crown Court was told on Wednesday.
Monks, 24, and Skarnes, 19, deny conspiring to murder the couple while they slept.
The court heard a transcript of a police interview with Skarnes, in which he told detectives Monks had asked a number of people he met on the internet if they would kill his parents for him.
Skarnes claimed he had not realised Monks was serious about the request until he visited him at his home in Preston Road in February for the first time, after weeks of chatting online.
Skarnes told the police: "He said he could not do it himself because they were still his parents. At that time, I thought he was joking.
"While I was down there (in Monks' home), it became more serious."
Skarnes said Monks began to discuss methods of killing his parents while they played a video game in the living room.
Skarnes told detectives: "He said a pillow or just throttle them with bare hands.
"I just laughed it off. At that point, we were just messing about. We were playing games while his mother was hoovering and his father was in the back.
"At that point, I still thought it was a joke."
Skarnes claimed he only realised his boyfriend was serious about murdering the couple as the afternoon wore on and he began to feel uncomfortable about their conversations.
He left the house in the evening, wishing Mrs Monks a "nice night", and went to wait at a nearby playpark until Monks texted him to tell them his parents were asleep.
Skarnes, of Ellesmere Port, Merseyside, told police he was scared he would lose Monks, his boyfriend, if he did not go through with the plan, adding he had few other friends and had been promised a place to live by Monks.
He said: "In my heart of hearts, I didn't want to do it.
"I thought it was too late to go back.
"I didn't want to go through with it, to kill.
"I didn't want to hurt his parents and I didn't want to hurt my boyfriend."
Skarnes claimed Monks had handed him a kitchen knife when he returned to the house, after telling his boyfriend he was sure he wanted the couple dead, starting with his father who was asleep upstairs.
He said: "I was really unhappy with the situation as it went on. I was trying to make him see if they were dead, he would be screwed on his own. He just said he would be fine."
Skarnes told police he knew he could not go through with the plan when he saw Mr Monks lying in bed, but that he dropped the knife when the dad-of-three woke up and a tussle began when he picked the blade up.