Authorities are looking for Adam Mayes, a 35-year-old family friend accused of abducting Jo Ann Bain and her daughters. Mayes was at the Bains' house helping them pack to move to Arizona when the mother and her three daughters vanished April 27, authorities said.
The bodies of Bain and her 14-year-old daughter, Adrienne Bain, were discovered late last week and positively identified. The FBI did not say how the two died.
The FBI said it believed the other daughters -- 12-year-old Alexandria and 8-year-old Kyliyah -- were still with Mayes. The agency did not say why it thought that, and FBI spokesman Joel Siskovic said no further details were available on the deaths or the search for Mayes.
FBI agents in green camouflage, carrying high-powered rifles joined K-9 units and SWAT teams in a search of the woods and back roads of north Mississippi near Mayes' home.
State troopers stopped vehicles and looked in trunks Monday, and FBI agents searched the yard of a home in rural Union County, seeking clues.
Mayes was last seen a week ago in Guntown, about 80 miles south of the Bain family's home in Whiteville, Tenn.
Siskovic said authorities talked to Mayes early on in the investigation, but he fled when they tried to contact him again.
The search for Mayes, considered to be armed and dangerous, will be a 24-hour effort, said Jimmy Edwards, sheriff of Union County. The area has a mix of heavy woods and farmland, and is crisscrossed by two-lane back roads.
"We don't have anything to confirm or deny his whereabouts. We're still searching," Edwards said.
Flyers with the girls' photos and descriptions were being distributed in Tennessee and Mississippi.
Jo Ann Bain's Facebook page showed in the days before she vanished she was packing and working on homework. Her last post, dated April 26, said "a good venting always makes you feel better." It didn't say why she was venting.
Mayes and the Bains were known around Whiteville, a town of about 4,500 people 60 miles east of Memphis. Mayes was a longtime friend of Bain's husband and had been at their home the evening before they disappeared, police said.
Both Gary Bain and Mayes were once married to sisters, Tennessee Bureau of Investigation spokeswoman Kristin Helm said.
Mayes had stayed over at the Bains' house to help the family pack and load up a U-Haul to drive across the country to Arizona, Helm said. Gary Bain, who was at the house that night, awoke to find his wife, daughters and Mayes gone.
He couldn't reach his wife on her cell phone that day, and reported them missing when the girls didn't get off the school bus.
Linda Kirkland, a family friend and cook at the Country Cafe in Whiteville, said the woman and her daughters were moving to Arizona because two of the girls had asthma.
Mayes also has ties to Arizona, Texas, North Carolina, South Carolina and Florida.