"They called the police who arrived after 5am after they found out that cash, jewellery and electrical goods had been stolen."
Rita has reportedly been told the incident may be connected to the break-in at Simon Cowell's London home last week.
The insider told The Sun newspaper: "The police have told Rita she needs to look seriously into the possibility that this was an inside job and could be connected to a number of burglaries in the area, including the one at Simon's house."
Meanwhile, Simon has revealed he suspects the burglary at his mansion was an inside job.
He explained: "I think he had inside knowledge, definitely. He got up to the first floor and there were two doors, one to my bedroom and one to my bathroom which leads to a dressing room where the safe was.
"So he could have walked into my bedroom but chose the other door."
- Bang! Showbiz