WITHOUT A TRACE: Missing DC woman's mother still searching for answers after her disappearance

It has been six years since a single mother from Washington D.C. went missing. Unique Harris' disappearance remains unsolved and is still as much a mystery today as it was back in 2010.

But the missing person case is still open and Harris' mother said she will continue to canvass the neighborhood and hand out flyers until her last day if she has to in order to find her daughter.

"The last words I said to Unique was, 'I love you Yukee Pookie.' That's my nickname for her," said Valencia Harris. "We had a nice conversation on the phone. The boys were rambunctious on the background."

Unique, her two young boys and their 10-year-old cousin were getting ready for movie night in the family's new Southeast D.C. apartment. The boys said once the movie was done, they got in bed and left their mother on the couch. But when they woke up the next morning, she was gone without a trace.

"I think somebody saw her and they watched her, and they watched her for maybe those whole five weeks that she was here," said Unique's mother. "And when they felt they had an opportunity, they took it."

Valencia Harris believes her daughter was taken against her will. Early on, she theorized Unique may have been abducted from her own apartment after witnessing a homicide from her fourth floor window. It is an incident Unique told her mother about just days before she vanished.

There have been few clues in the investigation. But one thing Valencia said she is certain of - there was foul play in her daughter's disappearance.

"I don't need the detectives to tell me," she said. "I know my child better than every detective that has worked on her case. I know my child and I know my child would never ever, in a gazillion years, leave her children like this."

In the six years since her disappearance, Unique's mother said there have been six different detectives assigned to the case. She said most of them have either retired or moved on from the department. But Valencia Harris told us even if she is the last one standing, she will be there fighting for an answer on why her daughter disappeared.