CHARLESTON, South Carolina - The FBI is offering a $10,000 reward for information on a 4-year-old girl who disappeared in South Carolina.

The reward was announced during a news conference on Wednesday regarding the case of Heidi Renae Todd.

Charleston Mayor John Tecklenburg also told reporters that Heidi's mother was "brutally beaten" and is hospitalized. Interim Police Chief Jerome Taylor said an "unwelcome guest" was at the Todd home, but couldn't characterize the incident as a burglary.

Taylor said investigators are trying to "unravel . . . the motive."

Heidi was reported missing on Johns Island shortly before 6 p.m. Tuesday.

"There are many things that we do not know, yet, that we are still investigating, but there's one thing we know, and that is that Heidi Todd is missing, and we need everyone to be on the lookout for this young lady," Tecklenburg said at a noon press briefing.

The State Law Enforcement Division has asked law enforcement agencies across the state to look for the girl. She was last seen wearing pink pants and a blue shirt. Authorities have not issued an Amber Alert because of a lack of information on a possible suspect.

Tecklenburg said the mother is in fair condition and has provided "limited information" to investigators. The mother provided a "very, very brief" description of the man and said he was possibly Hispanic, Taylor said.

Four other children who live in the home are safe, and two were in the home at the time the girl disappeared, Tecklenburg said.

The child's father is a member of the U.S. Coast Guard and was out of town on training, Tecklenburg said. He has since returned and is with the mother at the hospital.

Agents with the FBI, the South Carolina Law Enforcement Division and the Department of Natural Resources were assisting Charleston Police and Fire officials with the search, and divers were seen searching a lake near the child's home, CBS affiliate WCSC reported. Helicopters were also deployed.

Tecklenburg said investigators are searching "everywhere" and aren't sure whether or not the child could have been taken in a vehicle.