Nine people are being held in custody after a student was shot dead in the street as she walked to a Lidl supermarket.
Police say they are “working round the clock” to find out who killed Aya Hachem in a drive-by shooting on Sunday.
Miss Hachem, 19, was an innocent bystander who was hit by one of several shots fired from a vehicle as she walked to a Lidl supermarket near her home, police said.
She died from a single wound to the chest.
Detectives have been granted an additional 36 hours by magistrates to continue questioning three men, aged 33, 36 and 39, all from Blackburn, on suspicion of her murder after their arrests on Monday.
On Wednesday, Lancashire Police said they had made six more arrests.
Three men aged 28, 31 and 35 were held on suspicion of murder and two women aged 19 and 26 and a 29-year-old man were detained on suspicion of assisting an offender.
Police believe Miss Hachem was not the intended target of the attack, which took place in broad daylight on a busy main road near a Lidl supermarket in the town centre.
The Lebanese-born teenager, a second year student at the University of Salford, died in hospital a short time after emergency services were called to the scene in King Street at around 3pm.
Senior investigating officer Detective Superintendent Andy Cribbin, from Lancashire Constabulary’s force major investigation team, said: “Our inquiries are very much ongoing and we are working round the clock to find out who was responsible for Aya’s death.
“Our determination to get justice for her family remains undimmed and our thoughts are very much with Aya’s loved ones.
“I would like to thank those who have come forward to assist the investigation so far and I would continue to ask that anyone who has any information, however insignificant they may think it is, to get in touch."
Miss Hachem's family described her as "the most loyal, devoted daughter" who died in the "most horrific circumstances".
"She excelled in her studies both at Blackburn Central High School and at Salford University where she was in her second year and dreamed of becoming a solicitor," her family said in a statement.
"She had just completed her exams and was learning to drive.
"We her parents are absolutely devastated by her death and would like to take this opportunity to plead with any members of the public who may have any information however small that may bring those responsible to justice."
Anybody with information should contact 101, quoting log number 0412 of May 18, or anonymously via Crimestoppers on 0800 555 111.
