Detectives investigating the murder of an "inspiring" Lebanese-born law student have arrested three men in connection with the drive-by shooting.
Aya Hachem, 19, from Blackburn, northern England, was shot dead by assailants on a moving car as she walked to a supermarket on Sunday afternoon.
Police officers do not believe that the part-time charity worker, whose parents fled Lebanon as refugees, was the intended target of the attack.
Three men, aged 33, 36 and 39, from Blackburn have been detained in police custody on suspicion of murder.
On Tuesday, a fundraising page set up to build a mosque in Ms Hachem's memory had received £35,000 in donations.
Ms Hachem, who was in her second year of law at Salford University in Greater Manchester, had ambitions of becoming a solicitor.
Detective Superintendent Andy Cribbin, from Lancashire’s Force Major Investigation Team, said: “There is no evidence to suggest Aya was the intended target of this attack, and every indication is that she was an innocent passer-by, making this all the more tragic.
"We are determined to find who did this to Aya, particularly for her family, who are understandably devastated at their loss. Our thoughts remain with them," he said.
“We are also continuing to stress that the incident is not being treated as terrorism-related or a racially motivated attack.”
Shots were fired from a light green Toyota Avensis as it drove past Ms Hachem at 3pm on Sunday. Police later found the car abandoned. Officers are urging witnesses or anyone with information about the incident to make contact.
“We are on with a number of lines of enquiry, which includes looking at CCTV in the area and we have spoken to a number of key witnesses," Det Supt Cribbin said.
“Despite that, and the arrests, this is a live investigation and I am asking anyone who might know anything about what happened, or the circumstances leading up to Aya being senselessly killed, to speak to us.
"Any piece of information, no matter how insignificant it may seem, could prove vital to our investigation.”
In a statement, Ms Hachem's family have described her as a "loyal" and "devoted" daughter.
"Our beautiful 19-year-old daughter Aya has been taken from us in the most horrific circumstances," they said.
"She was the most loyal devoted daughter who enjoyed spending time with her family especially her brothers and sisters Ibraham, Assil and Amir.
"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. 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."
Tributes have poured in for the teenager, and the Muslim women's charity Global One has launched a second fundraising campaign to build water wells for vulnerable women and girls in communities where water is scarce.
Ms Hachem had volunteered as a young trustee at the Children’s Society.
Its chief executive, Mark Russell, said that all at the charity were deeply saddened to learn of her death.
"She was a truly remarkable young woman, and an inspiring voice for children and young people," Mr Russell said. "Our thoughts are with her family at this awful time."
The Deputy Chief Constable of Lancashire Police, Terry Woods, said her family was "utterly distraught".
"This was an appalling and senseless attack on an innocent young woman, whose life was cut short while she was simply out doing some shopping," DCC Woods said.
"First and foremost our condolences are with her family, who have lost their daughter during the holy month of Ramadan.
"For her life to have been cut short like this is unthinkable and her family are understandably utterly distraught."
Following the incident, armed police officers have been deployed to patrol the streets of the town.