Detectives say Martina Westcott shot 33-year-old Terrell Bruce once in the head while he was driving, before he barreled into another car.
Terrell Bruce's family says Westcott is an ex-girlfriend who couldn't take no for an answer.
"Just to get that phone call and then have to speak to detectives about my brother - it hurt. And it still hurts," said Natalye Kirkland.
Kirkland choked back tears as she relived the moment she learned her older brother was dead.
The 33-year-old was shot at point blank range in the head while driving on Walnut Lane before crashing into another car.
24 hours later police arrested 27-year-old Martina Westcott for his murder.
"She needs to understand who she really took from us, and to do this because you're heartbroken. He did nothing wrong. Terrell wasn't a person who held grudges. She knew that and she took advantage of that," Kirkland said.
Family members say Westcott was an estranged ex-girlfriend.
Detectives say the pair were apparently arguing in the car moments before she pulled the trigger.
The handgun was later recovered.
Philadelphia Police Capt. James Clark says, "She told her mother what had happened. Her mother took her to the 14th police district in Germantown. They brought her down to homicide. She gave a full confession."
The gathering of people at the crash site Wednesday night only illustrated the many lives he had touched through his job as a realtor and philanthropy work.
"From starting a non-profit in his brother's honor to starting scholarship funds to help kids pay for school in the city, he's done so many good things for so many people. I've never run across one person that had something bad to say about him," said family friend Donald Brown.
The family was celebrating the birthday Tuesday of their youngest brother who passed away years earlier, only for Bruce to die the same day.
Westcott was also not licensed to carry a firearm. She faces a number of charges, including murder.