Sheriff's deputies responded to the area of Highway 54 and Park Office Drive just after midnight Saturday.
When they arrived, they found three women - 24-year-old Amesha Smith, 23-year-old Alexandria Pierce and 22-year-old Adrianne Stevens - shot to death inside a vehicle.
The body of a fourth person, a man, was found outside the vehicle. He too had a gunshot wound.
Police later said the man, 23-year-old Brinton Millsap, killed the women before turning the gun on himself.
"It's an ugly senseless tragedy, but I know Amesha is resting with the Lord," Smith's mother Aduffie Page said. "I know she's in a better place. I'm going to miss her. I miss her, but she's in a better place. And I know the Lord is going to take care of her, until I get there to join her."
Page says all four apparently spent years in school together and that Smith and Stevens were especially good friends.
"I believe she died protecting a friend, being a friend," she said. "I think those three girls were together supporting each other. It's just tragic."
The Durham County Sheriff's Office says none of the four had a criminal history.
On Monday, Millsap's friend Ira Davis told ABC11 the man he knew was a good person and he's struggling to understand what happened.
"I don't know if he was depressed or what. Brit was a good guy," said Davis.