Amanda Knox allegedly exhibited strange behaviour after the murder
Meredith Kercher murder suspect Amanda Knox "turned cartwheels" in the police station after the killing, a police witness told a court in Perugia, Italy.
Former flying squad chief Domenico Profazio said he had to tell Ms Knox and her boyfriend Raffaele Sollecito their behaviour was "not appropriate".
Mr Profazio also listed DNA evidence allegedly incriminating the couple.
Ms Knox and Mr Sollecito deny killing Miss Kercher, 21, of Coulsdon, Surrey, who was stabbed in Perugia in 2007.
Mr Profazio said Ms Knox, 21, and Mr Sollecito, 24, had a "strange attitude" when they were brought to the police station for questioning, following the discovery of Miss Kercher's body in the flat she shared with Ms Knox.
He said that on one occasion Ms Knox sat on Mr Sollecito's lap.
"I told them it was not appropriate," Mr Profazio said.
He also recalled other officers reporting that Ms Knox was doing cartwheels and splits in the police station.
Mr Profazio told the court that records showed that Ms Knox's and Mr Sollecito's mobile phones were switched off from 2030 local time on the night of the murder, making the devices' whereabouts untraceable.
Amanda Knox and Raffaele Sollecito appear in court
Another witness, police officer Marco Chiacchiera, said no record had been found of a telephone call Mr Sollecito claimed to have received on his home landline at 2300 local time.
The court was also due to hear testimony from forensic detectives who inspected the apartment where the body of Miss Kercher was found on 2 November, 2007.
The prosecution alleges Miss Kercher was killed during a violent sex attack by Ms Knox, Mr Sollecito and a third man, Rudy Guede.
It maintains it has DNA evidence on a knife and on Miss Kercher's bra allegedly linking Mr Sollecito to the student's death.
Last year Guede was convicted of the killing and sentenced to 30 years in jail. He had admitted to being in the house at the time of the murder but denied any wrongdoing.
Ms Knox's defence team says any DNA evidence may have been "contaminated" and that Ms Knox was not in the house on the night of the killing.
Correction 15 March 2009: An earlier version of this story stated that Rudy Guede had pleaded guilty to the killing of Meredith Kercher It has been amended to make clear he had denied the offence but was found guilty.
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