That was more than two years ago.
Since then, the janitor's wife was found slain in a suburban Maryland hotel
. And the janitor was found dead in a Washington park. But there's been no sign of Relisha.
Investigators began a new, two-day search for the girl Wednesday at the National Arboretum, D.C. Metropolitan Police Chief Cathy Lanier told reporters.
A team of about 60 investigators, including divers and K9 units, are searching for the girl on land and in the water, she said.
Lanier declined to specify what details in the investigation led them to the arboretum.
"I really don't want to speak on the specifics of what we're following up on today," she told reporters.
Authorities didn't reveal whether they found anything after a day of searching. They're scheduled to return to the arboretum Thursday.
The 446-acre U.S. National Arboretum, in Northeast Washington, includes gardens, ponds and wooded areas on its grounds.
Lanier wouldn't specify where search teams were looking, but said their search would include a body of water.
"It's not a large body of water," she said, "but it's going to take the divers some time to get through it."
The search for the missing girl has stretched for two years. Authorities issued an Amber Alert after they found Andrea Denise Tatum slain at a Red Roof Inn in suburban Maryland in March 2014.
Police quickly identified her husband, Kahlil Tatum, as a suspect
in the slaying. They also said they were searching for him in connection with Relisha's disappearance.
At the time, Tatum, 51, was working as a janitor at the shelter where Relisha had been living with her family.
The FBI released surveillance video from February 2014 that showed the 51-year-old janitor and the girl with pink galoshes walking together down the hallway of a Washington hotel.
As they combed a Washington park for signs of the missing girl, they found Tatum dead in an apparent suicide
Authorities have searched areas of the U.S. capital for her a number of times since her disappearance, including a search of a construction site in December.
That search failed to turn up anything significant, CNN affiliate WJLA reported