Vincent Tabak was drinking champagne the night after killing Joanna Yeates, a court has heard.
The 33-year-old was described as "tired and disinterested" after strangling Miss Yeates with his bare hands the previous evening.
But he still found time to drink champagne as he joined girlfriend Tanja Morson at a friend's birthday party on Bristol's harbourside, the jury was told.
Miss Yeates, meanwhile, was said to have told friends she was "dreading" spending the weekend alone on December 17 last year, hours before she was strangled to death by next-door neighbour Tabak.
Linda Marland said she had chatted to Tabak the next day as her daughter Elizabeth celebrated her 24th birthday at the Pitcher and Piano. Mrs Marland told Bristol Crown Court: "Vincent sounded tired and disinterested. He was being short with his answers, not elaborating. I found it quite difficult.
"He only looked at me once. The rest of the time he was staring up the room. I got the impression Vincent was bored with my conversation... he was drinking a glass of champagne."
Dutch engineer Tabak admits manslaughter but denies Miss Yeates' murder.
The court heard from a string of friends who had drunk with Miss Yeates on the night of her death. Miss Yeates confided in one colleague of her fears at being without boyfriend Greg Reardon, who was visiting family in Sheffield.
The 25-year-old, who worked as a landscape architect at BDP, told office manager Elisabeth Chandler that she planned to spend the weekend baking.
"Jo told me that she was dreading the weekend because it was the first time she was going to be left on her own," she said in a written statement read to the jury. "Her partner Greg, who I know, was going away."