Detectives have been granted a further extension to continue questioning three men being held in connection with the killing of nine-year-old Olivia Pratt-Korbel.
Merseyside police said a 34-year-old man, who was arrested on suspicion of murder and attempted murder, a 41-year-old man and a 29-year-old man, who have both been arrested on suspicion of assisting an offender, are being kept in custody for another 36 hours.
A spokesman for the force confirmed the extension in a statement shortly before 9.30pm on Monday. The three were arrested on Sunday.
Another 34-year-old man, who was the fourth person arrested in the space of 24 hours, is still being interviewed by detectives.
The man, from Liverpool, was arrested on suspicion of assisting an offender after he was stopped by officers on the M42 in the Midlands, the force said.
Olivia died after she was shot in her home in Dovecot, Liverpool on 22 August when a gunman chased a convicted burglar, Joseph Nee, into the property at about 10pm.
A postmortem examination found the medical cause of her death was a gunshot wound to the chest. Her mother, Cheryl, was also injured.
DCS Mark Kameen said: “I continue to urge anyone who has information that can help our investigation into Olivia’s tragic murder to please come forward so we can bring those responsible to justice.
“A number of people have been arrested in respect of this investigation.
“However, we still need the public’s help in ensuring that we can build a strong evidential picture so justice is served for Olivia and her family.
“With this, I appeal for those who may have information, no matter how small, that could continue to help our inquiries, to contact us directly or anonymously and we will do the rest.”