(CNN) -- People from Florida to Ohio are being asked to help track down 12-year-old Brittany Mae Smith and her alleged abductor, Jeffrey Scott Easley, who was her dead mother's boyfriend.
Roanoke County, Virginia, County Police Chief Ray Lavinder said authorities have received more than 500 tips about Brittany and Easley. But three days after Virginia authorities found the body of 41-year-old Tina Smith inside her and Brittany's Salem home, they have few hard leads of the pair's whereabouts.
"I certainly hope they're in one spot and not moving, maybe in a garage somewhere," said Lavinder. "I simply don't know, and it does give us a lot of concern."
Lavinder said law enforcement groups in Ohio, North Carolina and West Virginia are being urged to issue Amber Alerts for young Brittany. Virginia issued one Monday, Florida did so Wednesday evening and Alabama posted its Thursday. The National Center for Missing and Exploited Children is working to put up billboards featuring Brittany's picture in those six states.
Acting on a tip Thursday morning, Palm Beach County Sheriff's deputies picked up someone that matched the description for Easley -- but it didn't end up being him, said Teri Barbera, the office's spokeswoman.
That had been one of searchers' few promising leads thus far, said Lavinder, noting there have been no "positive sightings" of Brittany or her alleged kidnapper since Sunday night.
Earlier this week, Lavinder described Easley as a "friend of the family," saying he met Tina Smith online this summer and he moved into their house in October.
Three of Brittany's aunts spoke at Thursday's press conference, including Angel Spangler, who urged Easley to "do the right thing" so that the seventh-grader could be on hand for her mother's still unplanned funeral.
"Brittany, we want to have good times with you again, and we want you to come home," said Rhonda Blanton. "Mr. Easley, please let Brittany come home for Christmas."
The search began after Tina Smith's co-workers called police, worried after the normally reliable woman failed up to show up for work Monday. After finding Tina Smith's body, police discovered that Brittany was not at school and issued the alert.
Virginia police have said the girl was abducted by Easley, but they do not know if Brittany went willingly with him. A felony abduction warrant has been issued for Easley's arrest.
Authorities found Easley's car relatively early in the search, but they have not yet tracked down a silver 2005 Dodge Neon four-door sedan with Virginia tag XKF-2365 that belonged to the girl's dead mother.
On Wednesday, Roanoke County police released a surveillance photo dating from last Friday showing whom they believe to be Brittany Smith and Easley at an area Walmart. Lavinder said they bought a blue, domed tent there.
Authorities have searched campgrounds, parks and parking lots around the region, but they have not yet found any evidence of Brittany, her alleged abductor or the tent, the chief said Thursday.
Easley is 5 feet, 11 inches tall, has brown hair and hazel eyes, according to the Amber Alert. While he once weighed 265 pounds, Lavinder said that he's lost weight recently and now is closer to 215 pounds. Brittany Smith is 5 feet tall, weighs 100 pounds, and has straight brown hair and brown eyes.
They have asked anyone with information to call 911 or Roanoke County police at 540-777-8641.