Investigators had planned a news conference on Tuesday to announce a murder warrant for 19-year-old Daniel Shelley of the 1700 block of Peach Street.
Instead, they announced his arrest as Shelley surrendered to police earlier in the morning.
Shelley will be charged in the shooting death of 31-year-old Hafeezah Nuri-Din, who was shot around 8:00 p.m. on Saturday in the 5800 block of Malvern Street.
Police say Nuri-Din had just left her parents' house and was about to get in a car with her father to be driven home when a group of males ran past her on the sidewalk.
At the same time, another man at the end of the block, now identified as Shelley, allegedly fired 10 times, hitting Nuri-Din twice in the back.
She was driven by her father to Lankenau Hospital, where she died.
Police say Shelley may have been involved in a dispute with the men in the group.
Shelley was the only gunman being sought. The gun used in the crime has not yet been recovered.
He will be charged with murder.
"It's not right, it's not fair," said Latifah Salaam, the victim's sister, told Action News on Sunday.
Salaam is still trying to grasp how something like this could happen.
"She was a beautiful person. She loved all her children, she was a good mother, a good wife, a good sister, good to everyone. She didn't deserve this," said Salaam.
Family members tell Action News that Nuri-Din recently realized her dream by opening up a pre-school for children in her neighborhood.
"She was living her life, raising her children, doing what she had to do," said Aisha Azziz, the victim's cousin.
"How can you come and gun someone down and still sleep at night?"