FORT WAYNE, Ind. — The FBI joined the search for a missing 9-year-old Indiana girl with physical and emotional problems Monday as agents descended on the mobile home park where she lived and that's a known haven for registered sex offenders.

Authorities in Fort Wayne planned to meet Monday afternoon to plan their next move after two straight days without a search for Aliahna Lemmon, who has been missing since Friday, said Cpl. Jeremy Tinkel, a spokesman for the Allen County sheriff's department.

About a half-dozen people in black windbreakers, several of whom identified themselves as FBI agents, were at the mobile home park Monday where Aliahna went missing from a family friend's home. Some with search dogs were seen at a nearby storage facility.

Tinkel said earlier a new search wasn't planned for Monday unless new leads arise through tips from the public or interviews.

Police haven't said why they called off the search after one day and aren't searching again. They also haven't said what they think happened to Aliahna.

Agents at the scene wouldn't say why the FBI was involved. An agency spokesman didn't immediately return phone calls and e-mails seeking comment.

More than 100 emergency workers conducted an extensive search Saturday for Aliahna around the rundown mobile home park on Fort Wayne's north side where she was last seen. No active search was done Sunday for the girl.

According to a state website, 15 registered sex offenders live at the mobile home park that numbers about two dozen homes.

Elizabeth Watkins, 52, who has lived at the park for six months with her 4-year-old granddaughter, said it's well-known that several sex offenders live in the neighborhood.

"It's scary," she said. "I don't know how a parent could leave their child alone."

Aliahna's mother, Tarah Souders, 28, told The Journal Gazette her daughter has vision and hearing problems and suffers from attention deficit disorder and emotional problems. She also has a history of sleepwalking, family members said.

Aliahna and her sisters were staying at a family friend's nearby home because their mother had been sick with the flu and Aliahna's stepfather works at night and sleeps during the day, The Journal Gazette reported Monday.

Mike Plumadore, 39, told the newspaper Sunday that he left the three girls in his mobile home about 6 a.m. Friday and went to a gas station about a mile away to buy a cigar. Authorities have said the store's surveillance video shows him there about that time.

"I had deadbolted the door," he said. "When I got back, all the girls was here."

He said he smoked his cigar and went back to sleep, then woke up about 10 a.m. when Aliahna's mother called. After that call, he realized the door to the home was unlocked and that Aliahna was gone. He said Aliahna's sisters, both 6 years old, told him that Aliahna had left with her mom.

Plumadore said it wasn't until he talked with Aliahna's mom about 8:30 p.m. that they realized she was missing and police were notified.

Tarah Souders said miscommunication between the two of them caused the delay in determining that Aliahna had vanished.

"She's never wandered off," Souders said. "She's never done anything like this before."

But Aliahna does have a history of sleepwalking, even unlocking doors and going outside while sleeping, said her grandmother, Amber Story.

"I just hope that she's not suffering or in pain," Story said.

Souders said her daughter also has vision and hearing problems and suffers from attention deficit disorder and emotional problems.