Detectives have arrested a man on suspicion of murdering 86-year-old Una Crown.
The 58 year old was arrested in Wisbech this morning (Thursday) on suspicion of murder.
He is currently in custody at Thorpe Wood Police Station.
Mrs Crown was discovered in her home in Magazine Lane at 10.45am on Sunday, January 13. She had been stabbed, and her body set on fire.
She was last seen alive on Friday, January 11, but had spoken to a friend by telephone on the Saturday.
Anyone with information is asked to call police on 101 or Crimestoppers, anonymously, on 0800 555 111.