Crimestoppers is offering £200,000 for information about the murder of nine-year-old Olivia Pratt-Korbel.
The record award will go to anyone that provides information leading to the conviction of those responsible. A £100,000 sum was offered by a private donor, and the charity's founder Lord Ashcroft has matched the amount, creating the single biggest reward offer in history.
Olivia Pratt-Korbel died after a masked gunman opened fire as he chased a convicted burglar through the door of the home she shared with her mother and two older siblings in Dovecot, Liverpool. Her death on August 22 followed months of growing tensions in the area and is thought to have been the latest incident in a series of tit-for-tat gang attacks.