CHICAGO (CBS) — Chicago police are looking for the gunman who killed a 21-year-old woman while she was in a car with her twin sister and two young nieces after a night of trick-or-treating.

The victim died just south of Blackhawks Park.  Police said she was shot twice in the head after she refused to give a masked gunman her phone.

An inconsolable Carlos Coronel cried as he talked about his daughter, Maira Thursday morning.

According to the family, the 21-year-old was shot to death while sitting in the passenger seat of a black BMW around 9:20 Wednesday night. Her older sister Leticia Coronel said her family is devastated.

“We just want the people, if they know something about it just let us know and the police,” said Coronel.

According to the family, Maira was trick-or-treating with her twin sister and two nieces, ages one and two years old when they were approached on the street by a masked gunman dressed all in black.

He forced them into the BMW and order Maira’s twin to drive. The gunman then demanded Maira’s money and phone.

She gave him $40, but refused to give him her phone. That’s when he shot her twice in the head, got out of the car and ran.

Her family can’t understand why it happened.

“She was a loving, young girl. She just worked all the time,” said Leticia Coronel.  “She was a kind person. She never do anything to anybody.”

Crisis responder Andrew Holmes had this message for Maira’s killer:

“You need to turn yourself in because I can guarantee you if your fingerprints are all over that car, save your mother and father that headache and turn yourself in,” said Holmes. “Because it won’t be a matter of time, especially if you’re in the system already.”

No one else in the car was hurt but the family says they were all traumatized.

So far there are no arrest in this case, but there are several surveillance cameras in the area which investigators hope will help them identify the killer.