A man has been arrested on suspicion of the murder of nine-year-old Olivia Pratt-Korbel who was shot dead in her home in Liverpool.The schoolgirl was shot on Monday night by a gunman who chased his intended target into the family home in Dovecot, also injuring her mother Cheryl, 46.Merseyside Police said a 36-year-old man, from the Huyton area, had been arrested on suspicion of Olivia’s murder and two counts of attempted murder after an operation involving armed officers on Thursday night.