“Once I cut off the rope around his hands and legs and stripped the duct tape off his eyes, mouth, nose and throat, he seemed to be in a state of panic, gasping for breath, reaching out to his wife and then taking his little girl into his arms,” officer Christos Vardikos told the court.

“But once he was set free and we moved away from the bedroom he turned extremely calm.

“I was with him for the next four to five hours and not once did he break down or turn to me to say, ‘f—k, my wife has been killed. What has happened to me?’

“In the 30 years I have been in the force, I have never seen someone react so calmly to the ferocity of such a crime.”

The officer said that as soon as Mr Anagnostopoulos was untied, he sat on the bed where his wife lay dead, poking her body.

“He asked, ‘Honey, are you OK?’ We told him that it’s over, she is dead,” said Mr Vardikos.

‘Calm and indifferent’

The couple’s baby, 11-month-old Lydia, was “calm and silent” beside her mother’s body.

A second police officer, Kleanthis Antonopoulos, said: “We escorted him out the room and took him outside the house. He seemed calm and indifferent – even when we passed the sight of the hanging puppy.”

As the suspicions of detectives grew, Mr Anagnostopoulos attended a memorial service to his wife in Alonissos last June.

It was there that he was arrested and a few hours later confessed to the killing. He claimed that he had suffocated his wife in a fit of rage because she had threatened to leave him. He also said she had been violent towards him.

He was caught out by data gleaned from his mobile phone and Ms Crouch’s smartwatch, which revealed inconsistencies in his account of the supposed home invasion.

Information from the smartwatch, which recorded Ms Crouch’s heartbeat, suggested that it took Mr Anagnostopoulos six minutes to strangle his wife to death.

Information from his mobile phone showed that he was moving around the house at the time when he claimed he had been trussed up.

Mr Anagnostopoulos faces up to 25 years in jail for killing his wife, plus a separate maximum 10-year sentence for killing the family dog.

The couple’s daughter is being brought up by Miss Crouch’s British father and her Philippines-born mother on Alonissos. The next hearing in the trial will be on Thursday.