FAIRFAX COUNTY, Va. (WFXR) — A missing person poster shared by a Roanoke nonprofit may have been the clue that helped Virginia investigators get one step closer to identifying the fourth victim of a man authorities are calling the “shopping cart killer.”

A flyer of 48-year-old Stephanie Harrison of Redding, Calif., is the reason why Fairfax County investigators are heading to California to gather DNA samples.

(Photo: Courtesy The AWARE Foundation, Inc.)

With the help of The AWARE Foundation, Inc. in Roanoke, Harrison’s sister posted about 300 of these flyers across northern Virginia and Washington, D.C.

According to the president of The AWARE Foundation, Inc., Kenny Jarels, “We still need to know if some of the missing cases that we had listed for quite some time now happens to be more of his victims.”

Harrison was last heard from on Aug. 19 before heading to the Capitol building in Washington, D.C.

Bank records show that she last checked in to the Moon Inn Motel in Alexandria, which is where police say 35-year-old Anthony Robinson lured victims after meeting them on dating sites.

Fairfax County Police Department confirmed with 8News that they are investigating whether Harrison was the fourth victim.

(Photo: Courtesy Harrisonburg Police Department)

“He preys on the weak, he preys on the vulnerable, and he does unspeakable things with his victim,” Fairfax County Chief of Police Kevin Davis said during a press conference on Friday, Dec. 17.

Robinson was originally arrested on Nov. 23 in Harrisonburg after police found the bodies of two missing women — 54-year-old Allene Elizabeth “Beth” Redmon of Harrisonburg, and 39-year-old Tonita Lorice Smith of Charlottesville — in the same vacant lot near shopping carts, authorities say.

He was arrested after surveillance footage and phone records connected him to the killings, according to Harrisonburg Police Chief Kelley Warner. The two victims were reportedly found near each other in the same lot, but were killed at separate times.

Two more bodies — one of which is believed to belong to 29-year-old Cheyenne Brown of Washington, D.C., who disappeared back in late December — were uncovered on Wednesday, Dec. 15 in Alexandria in a wooded area near the motel where Harrison was last seen.

“The good thing is, he’s in custody,” said Davis. “The challenge that remains is identifying other victims.”

Police say they’re in the early stages of this investigation, adding that while Robinson is the main focus, there could be other individuals involved in these deaths.

According to the National Missing and Unidentified Persons System (NamUs), there are 290 open cases of missing persons in Virginia.