A 34-year-old man has been arrested over the murder of Olivia Pratt-Korbel who was shot in her home last month.
The nine-year-old was killed as her mother tried to stop a gunman entering their house in Liverpool on 22 August.
Olivia's mother Cheryl Korbel was also shot in the wrist as she tried to shut the door on the attacker.
The shooter had been chasing and firing at another man when Olivia was shot. Neither man was known to the family.
Merseyside Police said the suspect, from Dovecot, had been taken to a police station where he would be questioned by detectives.
The force has now arrested 10 men as part of the investigation, but no charges have so far been brought.
Olivia's funeral was held on 15 September at a packed St Margaret Mary's Church, just streets away from where the shooting happened.