Colin Howell used a note which his wife Lesley had written as part of his plan to cover up her murder, the jury heard.
He produced it when some members of Coleraine Baptist Church called with him at his home in Knocklayde Park after he had reported she had gone missing, according to Crown prosecutor Ciaran Murphy.
The note read: "Dear Colin, I am just trying to go to sleep now, how long for I don't know. Thank you for your help over the past few days and the good times in our marriage.
"I don't know what to say to you because I don't know how I feel. But I have seen that life goes on after a few weeks of pain and let's face it Colin I am nothing in comparison to what you lost in the one you loved a while back.
"If I wake up in the morning, just let this be our secret. Lesley."
Jim Flanagan, the court heard, was one of the people shown the note.
It was he and David Green, then a detective inspector, and also a member of the Baptist Church, who later found the two bodies in a car, parked in a garage behind a row of houses at Cliff Terrace, Castlerock, also known at the Twelve Apostles.
Number six was owned by Lesley's father, Harry Clarke, a retired company director, who collapsed and died in his daughter's home just days earlier.