donald graham , 62 , from sparty lea , northumberland , killed heiress and property developer janet brown , 45 , so he could fund his lavish taste in supercars and buy his second mistress a home .
ms brown vanished in 2005 and her body has never been found .
graham , who dubbed himself teflon don , was last year jailed for life with a minimum of 32 years for killing ms brown 's parents believing she was still alive but living abroad .
but jurors , who had been deliberating over the case for a week , found him guilty of murder and perverting the course of justice during a trial last year .