Search for 9-year-old girl who vanished on a New York camping trip enters critical stage

The family of Charlotte Sena, who went missing Saturday evening in upstate New York, is asking the public for help as authorities ramp up their search for the 9-year-old they fear could have been abducted.

Charlotte, who was camping in Moreau Lake State Park with her family, went on a bike ride with close friends around dinner time and never returned, officials said.

Police believe Charlotte could be in "imminent danger," according to an Amber Alert issued Sunday morning.

"Following our exhaustive search of the park we took that step of issuing the Amber Alert because we felt that that exhaustive search, when we couldn't find her here, it was quite possible that an abduction had taken place," said Lt. Colonel Richard Mazzone of the Uniform Force of the State Police.

When she disappeared, Charlotte was wearing an orange tie-dyed Pokémon shirt, dark blue pants, black Crocs and a gray bike helmet, according to a description provided by state police.

The number of people searching for Charlotte has grown to 400 people, state police said. They come from 34 volunteer fire departments and private groups as well as federal, state and local law enforcement.

The search area has expanded over 46 linear miles, authorities said.