After the killing, the man dressed in some of her clothing, including a skirt, swimsuit and plimsolls, Leeds Crown Court was told.
Dr Howe had just arrived at York University on 25 July last year when she was attacked. She suffered a 28-inch wound to her body, had her jugular vein cut and was stabbed through the heart.
Robin Pask, 32, a laboratory technician from Horwich, Greater Manchester, pleaded not guilty to her murder but guilty to manslaughter on the grounds of diminished responsibility.
Stephen Williamson QC, for the prosecution, told the court that Dr Howe, an Oxford graduate, was not known to Pask. Pask, married with three daughters, had completed two parts of his degree course and had gone to York to work on studies unconnected with Dr Howe.
Mr Williamson said that in May last year, Pask had been granted a conditional discharge after pleading guilty to causing criminal damage at the home of a young woman living next door to him.
Last July, Pask set off for York University and took with him a sharp kitchen knife. He bought a second knife, saying later he had planned to kill himself. Mr Williamson said that Pask walked into Dr Howe's room at the university near to his own room at Wentworth college on the campus. He said: 'Dr Howe fell or was pushed to the floor. Her dress was cut and torn from her body and she was left naked except for the sandals on her feet.'
Mr Williamson alleged that Pask had slashed Dr Howe's body with the knife, causing a 28-inch wound from her collar bone. The defendant had also sexually assaulted her.
The jury was told that Dr Howe was due to teach a summer school course for the Open University in York. Her husband, Jeremy, editor of Radio 3 plays, had dropped her off at Oxford station and never saw her alive again. A number of people in rooms near to where Dr Howe was staying had heard three high-pitched screams but saw nothing.
Mr Williamson said that after the killing, Pask had made a series of telephone calls to his relatives and had made sexual remarks to them. Pask was arrested in a car park in the early hours and was found to be wearing Dr Howe's plimsolls and skirt. Pask is alleged to have told police that he had drunk three-quarters of a bottle of vodka and some wine, and had taken amphetamine tablets.
The accused is said to have told the police he could not explain the attack and that there was no reason for it. He said: 'It was like it was somebody else. I just hit her with the knife. I don't know how many times or where and she was just laid on the floor. It was like I wasn't there.
'I can't explain it. I attacked her for no reason, absolutely no reason. I am not a butcher. I don't go around killing women or have any intention of killing women. But I did.'
Christine Pask told the court how her husband's behaviour had deteriorated steadily in the months before the killing. 'He slept a lot and was always tired and had no interest in coming out,' she said.
He had taken to drinking and she had found eight half-bottles of whisky, vodka and rum in a box in the bottom of the wardrobe.
Mrs Pask also noticed something odd about his behaviour before he set off for York. 'Normally we would say goodbye with a peck on the cheek but his time he gave me a long lingering kiss which was unusual, and he held me for a long time,' she said.
The trial continues today.