The FBI issued warrants Thursday for a couple suspected of kidnapping the woman's 9-month-old son from state custody after a social worker, later found dead, brought the child for a visit.

The warrants for Renee Terrell, 33, and her boyfriend, Christopher Wayne Luttrell, 23, were for unlawful flight to avoid prosecution on state kidnapping charges, said Tracy Reinhold, special agent in charge of the FBI in Kentucky.

"These are desperate people," Reinhold said. He would not say if investigators knew where they were.

The baby had been removed from Terrell's custody when he was 13 days old because of neglect, according to police. On Monday, Social worker Boni Frederick, 67, had taken the boy to his mother's home for a visit.

Frederick was found beaten to death at the house later that day, and the baby, his mother and Frederick's station wagon were gone, authorities said.

Police said Thursday they have received several reported sightings of the couple since then but few solid leads.

The most credible report came Wednesday from a truck driver in St. Louis, who said he saw the car and plate Wednesday afternoon, said Henderson Police Sgt. John Nevels.

Before that, they had been spotted late Monday at a gas station in Illinois, authorities said.

A neighbor, Jean Davis, told The Courier-Journal that Terrell learned last Wednesday that the missing boy, Saige, was to be put up for adoption. Terrell told friends on Saturday she planned to take the boy and run away to New Mexico, Davis said.

"She loved her baby," Davis told the newspaper in a story published Wednesday. "She talked about how she was going to get her baby and everything back. She was buying clothes. She had a baby bed and a high chair and everything. ... I guess it made her snap."