The 29-year-old father of two was gunned down this week at the Circle K near Southpoint.
His killer remains at large.
"Why does it have to be so tragic," Rose Lucas said. "Just want to take somebody's life at 2 p.m., in the middle of the day. There's nothing hard about life that you would want to do that to somebody."
Lucas spoke exclusively with ABC11 to say her son was not a troublemaker, but a young man thriving and happy after overcoming years of depression.
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She said her son was headed home Tuesday afternoon from work when he stopped at the Circle K at 109 N.C. 54 Highway.
"He texts his fiancée to say he would be home by 1 p.m. By six o'clock we hadn't heard anything. That was abnormal," she said.
Lucas learned about the shooting on the news.
It was her daughter who went to the police crime scene and confirmed it was Colby.
NEW: This is Colby Lucas. He was gunned down outside the @CircleKStores near @ShopSouthpoint. I spoke exclusively w/ his mom today. She believes the shooting was random. “He’s not a confrontational person.”— Tim Pulliam (@TimABC11) September 27, 2018
Lucas leaves behind a fiancé and two sons. @DurhamPoliceNC investigating pic.twitter.com/amzccMeQc4
"At the gas station she saw my car and we just knew it," Lucas said. "Police were on their way to tell us that it was him."
Lucas says she doesn't know who would want to harm her son. She thinks the shooting is random.
"He's not really a confrontational person. He keeps to himself," she recalled. "His laugh, it will never be seen again. I wanted people to know he's an angel now. He's a good person. In the blink of an eye, he is gone."
Police won't say whether the shooting was random and have not released details about a motive.
They have, however, interviewed a person of interest.
Colby's body is still with investigators.
His mom said he was set to get married next year.
A GoFundMe page has been set up to help with funeral expenses and to help care for his children. If you'd like to help, you can click here.
The funeral for Colby Lucas will be next Friday at 4 p.m. at New Hope Church in Durham, 7619 Fayetteville Road.
There will be a viewing at 3 p.m. followed by the service.
Anyone with information is asked to call Investigator D. Cramer at (919) 560-4440, ext. 29284 or CrimeStoppers at (919) 683-1200. CrimeStoppers pays cash rewards for information leading to arrests in felony cases and callers never have to identify themselves.