Even when he was given the news that his sister was dead Katen Patel could not bring himself to hug his brother-in-law because he knew “something was not right”.

The ITV programme scheduler had been with Fadi Nasri at the hospital when Mrs Patel-Nasri was pronounced dead in May 2006. Mr Patel took his brother-in-law into his home in Wembley, North West London, for the following days.

But although Mr Patel, 35, did not yet suspect his brother-in-law of any involvement in his sister's death, deep down he was troubled by his behaviour.

“When we were told by the doctor that Nisha hadn't made it I put my hand on his shoulder and said to him, ‘Don't worry, I'll look after you',” he said.

“But I could never give him a hug or reassure him things were fine. Even on the funeral day I never hugged him, I hugged all the other 600 people that turned up but not him.”

Mr Patel was due to get married three days after the murder. Instead he joined his brother-in-law at an emotive press conference to appeal for information about the brutal death of the special constable.

“I still didn't think he could be involved in any way but there was something inside me, I just couldn't put my arms around him,” said Mr Patel.

Although the couple appeared to have a good relationship during their three-year marriage, Mr Patel felt that it would not last because of their different personalities.

“Nisha was extremely organised,” he said. “He on the other hand was always out of the house dossing around, doing whatever he was doing. If she wanted him to do something, he would end up doing something else.”

Despite his reservations, Mr Patel trusted his brother-in-law until four months after the murder. Then, on the advice of police, Nasri admitted having an affair with a prostitute since the start of the year.

Mr Patel recalled: “Fadi said, ‘You know I wouldn't do anything to hurt Nisha, you know I loved her very much, but I've been seeing someone.'

“I thought, how could you do that? It was so disgusting. I said I needed some time to get my head around this and would call him. I had no intention of speaking to him after he betrayed my sister.”

Weeks later Nasri placed a legal restriction on Mr Patel's home demanding his wife's share of the property.

“I hated for what he done to Nisha and then despised him for his actions on my family home,” said Mr Patel.

Despite the admission of betrayal, Mr Patel said he was still not sure that Nasri was responsible for his sister's death.

“Even when I went to court for the first time I was going with an open mind that it could've be an accident or maybe it was a robbery gone wrong,” he said. “But looking at the facts, listening to the evidence, listening and watching his own actions, to me there's no doubt, it's conclusive.”

As he watched his brother-in-law cry in the dock at the Old Bailey, Mr Patel realised that he had seen the performance before. “Fadi was happy at his home but at my house he would always be upset and he would always cry in front of my family and friends,” said Mr Patel.

“If you leave your eyes open for a minute or so they automatically start watering, once they start watering then you'll start blinking and the tears start to drop.

“He did the exact same thing in the dock. You could see the tears come out but they were not real.”