UNION CITY, Ga. -- Someone opened fire at an apartment complex in Union City late Tuesday afternoon, and police said one person was killed and another has non-life-threatening wounds.

Witnesses say that at about 5:30 p.m. they heard gunshots at the Hidden Lake Apartments on Morgan Road, just off of I-85 and Jonesboro Road.

One resident, Lindsey Cooley, said she ran in the direction of the shots and saw that an SUV had rammed into the small mailbox building in the parking lot, and the SUV had come to rest against some trees.

She said she doesn't know if the SUV crashed while someone was shooting at it, or if someone fired the shots after the SUV crashed. But she saw bullet holes in the sides of the SUV as she ran up to it.

Union City police later said two people had been shot. Cooley tried to help the person who was most seriously wounded, but he died Tuesday night.

Worried residents said others could have easily been in the line of fire -- children play near there, and residents drive up to the mailboxes at all hours to check their mail.

Cooley said she did not see anyone running away, she was not able to ID a possible suspect.

Late Tuesday night police said they didn't know if the second person who was shot, the one who survived, had been inside the SUV or outside the SUV during the gunfire.

Investigators were working through the night to try to figure out who is responsible.

PHOTOS | Union City accident