The husband of a special Pc killed outside her home admitted to an affair after police confronted him with his lover's pictures on his mobile phone.
Nisha Patel-Nasri's husband is accused of organising the murder
Fadi Nasri met Lithuanian prostitute Laura Mockiene, three months before his wife's murder, and would meet her once a week, the Old Bailey heard.
Nisha Patel-Nasri, 29, died when she was stabbed outside her house in Wembley, north-west London, in 2006.
Mr Nasri, 34, and three other men from London deny her murder.
When Det Con Sid Shenoi confronted Mr Nasri with three mobile phone pictures of Ms Mockiene, he said they had become friends when they first met in February 2006, the court heard.
'Taller than him'
Giving evidence Det Con Shenoi said: "Fadi laughed and said that she was just a friend and he went on to say that he did not have a sexual relationship with Laura as she was taller than him."
But Mr Nasri called the officer later that day and admitted to the affair.
"He said that Laura worked as a cleaner in hotels and that he would meet her approximately once a week and they'd go to hotels for sex," the officer told the court.
Prosecutors allege Mr Nasri organised the killing in order to cash in on his wife's £350,000 life assurance policy.
Mr Nasri, who ran a limousine-hire business, told the officer Ms Mockiene had a six-year-old daughter who lived with her father in Lithuania.
Holiday with lover
Det Con Shenoi said: "He then said that Nisha was not aware of his extra-marital affair, and that Nisha was the jealous sort.
"He went on to say that he had just returned last week from Lithuania where he had spent three days with Laura," he added.
Earlier a statement from Mr Nasri read in court said his wife "only made friends" and despite rows, "Nisha was not the kind of person I could stay cross with for long".
He also said that he was "in a state of shock" when he heard about the stabbing.
Mr Nasri, from Barnet, north London, Jason Jones, 36, of Manor Park, east London, Tony Emmanuel, 42, of East Ham, east London, and Rodger Leslie, 38, of Barnet, all deny murder.
The case continues.