A wealthy Hampstead property developer accused of murdering his pregnant wife stashed documents about lie-detector tests and private investigators in his parents’ attic, a court has heard.

Robert Ekaireb, 39, who is alleged to have killed former lapdancer Li Hua Cao, 27, “tucked away” the contents of a wallet, a Chinese necklace and handwritten notes in the back of a wardrobe, the Old Bailey heard last week.

Det Con Mark Johnson searched the home of Ekaireb’s parents on June 7, 2012 - the day he was arrested for murder - and discovered bags of items.

A later search of one of the bags found a print-off of an e-mail, dated October 6, 2006, from “polygraphs101@aol.com” with a reference to their website, www.polygraphs.co.uk.

A necklace bearing Mandarin characters was found alongside handwritten notes.

One piece of paper bore the letterhead: “Worldwide Association of Professional Investigators”, the court heard.

Ms Cao has not been seen alive since October 23, 2006 after disappearing from the luxury flat she shared with Ekaireb in Pavilion Court, on the Mount Vernon estate, in Frognal Rise.

It is alleged Ekaireb murdered her following the breakdown of their relationship as a result of his jealousy and obsessive-compulsive personality.

Ekaireb, of Corrigan Close, Hendon, denies murder.

The trial continues.