A woman has been found guilty of murdering her sister by slashing her neck before leaving with her diamond-encrusted gold Rolex watch. Nancy Pexton stabbed Jennifer Abbott 10 times and then left her body for three days in her flat in Camden, north London , a court heard. On Wednesday, an Old Bailey jury convicted Pexton, 70, of murdering Abbott, a film director, on 10 June last year. Abbott, a 69-year-old US citizen, was last seen alive on a doorbell camera as she returned from walking her corgi Prince at 7.36am that day. Pexton spoke to her by phone at 11.36am and travelled by bus to her Mornington Place flat at 12.45pm, leaving an hour later. She then called her GP, reported taking an overdose and was taken to hospital where she stayed until her arrest on 18 June. On 13 June, a neighbour used a scaffolding pole to break down Abbott’s door after becoming concerned he could not hear her dog barking. Her niece Mai Pexton had been seen banging on the door and screaming for her “auntie”.…