A woman has been sentenced to life in prison for killing her sister at a north London flat before taking a valuable watch, the BBC reports.Nancy Pexton, 70, was found guilty of murdering her sister, film director Jennifer Abbott Dauward, at the victim’s home in Camden in June last year. She must serve a minimum of 22 years.Abbott, 69, was discovered dead in her living room days after the attack, with injuries consistent with a violent assault. Her mouth had been taped, and a gold Rolex watch she regularly wore was missing.The court heard that Pexton had visited her sister on the day of the killing and left the property about an hour later. She was arrested several days later, with the stolen watch later recovered from her belongings.Sentencing her, Judge Anuja Dhir