The husband of Jo Ann Bain, 31, reported his wife and the three girls -- 14-year-old Adrienne Bain, 12-year-old Alexandra Bain and 8-year-old Kyliyah Bain -- missing on April 27, according to the FBI. They were last seen in Whiteville, a town of about 4,600 people in western Tennessee.
The Tennessee Bureau of Investigation soon thereafter issued an Amber Alert asking for the public's help in finding the Bain sisters and their mother and for information leading to Mayes' arrest.
Aaron T. Ford, special agent in charge at the FBI's bureau in Memphis, Tennessee, told CNN on Sunday that investigators believe the victims "were transported across state lines into Mississippi."
Authorities' focus is now in Union County, Mississippi, where Guntown is located, the FBI agent said. Authorities have also pointed out, however, that Mayes also has connections to Texas, North Carolina, South Carolina and Florida and could be en route to Arizona.
"The immediate concern is that we capture Adam Mayes and that we return the kids and their mother back to their family," Ford said.
Beyond continuing to solicit information from the public on the case, authorities did not release any new substantive information Monday -- including more on the two found dead in Mississippi, and even why they believe Mayes is responsible for the four family members' disappearance.
"We have no new information at this time," Joel Siskovic, spokesman for the Memphis FBI bureau, said Monday to CNN affiliate WPTY. "We do consider Adam Mayes a danger."
Rick Foster, whose wife is a lifelong friend of Jo Ann Bain and whose daughter is a classmate of Adrienne Bain, recently told CNN that Mayes had been a friend of the Bain family for years. Mayes lived about 90 miles away in Mississippi, but would stay with the Bains when he was in the Whiteville area, Foster said.
He described Mayes, who was known on Facebook and around Whiteville as Paco Rodrigass, as "a big kid in a grown man's body."
Mary Patterson, Mayes' landlord in Alpine, Mississippi, told WPTY that she thought he was a "kind" and "fun guy."
"If somebody told me this, I would have never believed it," she said.
Authorities characterize Mayes as a white man who has blue eyes and brown hair, weighs about 175 pounds and stands 6 feet, 3 inches tall. He recently cut his own hair and may have done the same to the three children, according to the Amber Alert.
As for the Bains, Foster characterized the marriage between Jo Ann and her husband, Gary, as "perfect" and said the family planned to move to Arizona once the school year ends.
The FBI and U.S. Marshals Service are offering a $50,000 reward for information leading to Mayes' arrest and to the missing woman and her daughters.
CNN's Stephanie Gallman contributed to this report.
™ & © 2012 Cable News Network, Inc., a Time Warner Company. All rights reserved.