A 36-year-old man has been arrested on suspicion of the murder of nine-year-old Olivia Pratt-Korbel.
Merseyside police said: "We have arrested a 36-year-old man on suspicion of the murder of nine-year-old Olivia Pratt-Korbel.
"The man, who is from the Huyton area, was also arrested on two counts of attempted murder.
"The arrest came after an operation involving armed officers in the Merseyside area last night, Thursday, August 25.
"The man is currently in custody where he is being questioned by detectives.
"An investigation remains ongoing and anyone with information is asked to DM @MerPolCC or contact @CrimestoppersUK on 0800 555 111."
The man is currently in custody being questioned by detectives.
Olivia's family paid tribute to her, describing her as "unique, chatty, nosey little girl who broke the mould when she was born".
They added: "Although her life was short, her personality certainly wasn't and she lived it to the most she could, and would blow people away with her wit and kindness."
The family had urged people to "do the right thing" and said: "If anyone knows anything, now is the time to speak up. It is not about being a 'snitch' or a 'grass', it is about finding out who took our baby away from us."
Convicted burglar Joseph Nee, 35, from the Dovecot area of Liverpool, has been named as the intended target of the shooting.
As Olivia lay dying, he was picked up by friends in a black Audi Q3 and taken to hospital.
A message on a box of flowers left among tributes at the scene read: "So sorry for your loss of beautiful Olivia. Rest in peace, thinking of all family. Nee family."
Olivia's death came 15 years after 11-year-old Rhys Jones was shot dead on his way home from football practice in Croxteth, Liverpool.
Former Liverpool FC player Ian Rush and ex-Everton player Ian Snodin left flowers in Kingsheath Avenue on behalf of the Merseyside football clubs.
The two club ambassadors, Snodin wearing a suit with a blue tie and Rush wearing an LFC suit with a red tie, arrived at the police cordon at about 9.45am.
On the flowers from Everton FC, a message read: "RIP Olivia. No words will lessen the pain or explain such a tragedy.
"Our city stands united. Forever in our thoughts."
A card on the floral tribute from Liverpool FC said: "Rest in peace, Olivia, with deepest sympathy from all of us at Liverpool Football Club.
"You'll Never Walk Alone."