GREENSBORO — A year ago this week, a 22-year-old woman and her 2-year-old son were found dead in a tucked-away location in Greensboro. Police still are trying to determine a motive and find a suspect in the double homicide.

Asia LaRose Brown and her son, Ashton, were found in Brown’s Buick LaCrosse on Feb. 23, 2015, near the bank of South Buffalo Creek of Thurston Avenue. The car, purchased only days before the mother and son were found, had been set on fire. Police have not commented on whether an accelerant was used to start the fire.

The two were found in the trunk of the car.

The N.C. Office of the Chief Medical Examiner in Raleigh said in its autopsy reports that it was unable to tell whether they died prior to the fire.

Greensboro police continue to investigate the case, but they have developed little new solid information about what may have happened to the two since the end of April.

“This is probably the most challenging case since I’ve been in homicide,” said lead detective Mike Matthews, who has investigated homicide cases for more than 10 years. “It’s been one challenge after another.”

The challenges included a crime scene that was difficult to preserve because of snow and took more than a week to process; the conditions of the bodies, which required more detailed DNA analysis to confirm the identities; and the emotional toll that the death of a child takes on detectives.

Ashton’s death was the first of three homicides in 2015 involving children under the age of 3.

Police said Brown and her son often visited friends. The week before their deaths, they didn’t stay at their apartment, adding to the number of people police had to track down when reconstructing the last week of their lives.

Brown’s mother and brother declined to comment for this article.

From the beginning, police were working under the assumption that the bodies were Brown and her son. The two had been reported missing by a co-worker of Brown’s at Greensboro Auto Auction. Brown was reported missing on Feb. 22, after failing to show up for work for two days. The co-worker had repeatedly called Brown with no response and went to Brown’s apartment. There was no answer at the door.

Matthews said because the remains in the car appeared to be a female and small child investigators believed it was the Browns. The car also was traced back to Asia Brown, who bought the Buick and registered it at the N.C. Division of Motor Vehicles office in High Point on Feb. 20, the last day police believe she was alive. Officers received confirmation months later using DNA analysis from Brown’s parents and Ashton’s father.

“I have lots of leads and avenues I’m pursuing. There’s more than one avenue of investigation,” Matthews said.

Those avenues include people who had different relationships with Brown, he said.

Police have closely examined Brown’s text messages and social media accounts, in part because someone as young as Brown tends to be active on social media. Matthews said Brown was posting the morning of Feb. 20. He would not say exactly what time she stopped but did say that is part of the reason investigators are confident it is the day she died.

Matthews said police are still trying to construct a timeline of Brown’s final hours. She was last spotted at the AutoZone at 3033 Randleman Road about 3:20 p.m. On video camera recordings, Ashton was not seen with her. Before going to the AutoZone, Brown was at the DMV in High Point, with her son, Matthews said.

He said he wonders if Brown made a stop in-between the two locations.

“Did she stop somewhere to let someone keep Ashton?” Matthews asked. “That’s going to be very important to this investigation. We would love that information.”

If that’s the case, he urges the person with that information to come forward.

“We’ve worked on that feverishly through the follow-up,” Matthews said. “If he was left, it would have to be close to the AutoZone, based on where she was found.”

Police have not excluded the possibility that this was a random crime.

“Nothing’s been ruled in, nothing’s been ruled out, that’s where this investigation’s at,” Matthews said. “There are missing pieces to this case, like Ashton (not being with his mother at the AutoZone) that could greatly help this case. I need people to be focused on Friday afternoon, Feb. 20.”

Police are also considering just how the Buick got to the area off Thurston Avenue near South Buffalo Creek. The area is surrounded by businesses. The creek area, however is known for criminal activity, police said.

Where the car was found is hidden from the road.

“You have to know that area,” Matthews said.

He urged anyone with information about Brown and Ashton to come forward.

“We’ve turned over every rock in this investigation,” he said. “The whole division has assisted with the case.

“I will use all the resources the department’s given me to try to solve this case and bring justice for these two.”

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Contact Sarah Newell Williamson at (336) 373-7076, and follow @snewell_NR on Twitter.