(WKTV) - It's a race against time to find a missing person.
"It is usually a statistic that the first three hours are the most critical," says Wendy Fical, of the National Center for Missing and Exploited Children in Utica.
Sisters Delila Miller, 7; and Fannie Miller, 12, disappeared after walking to their family's roadside farm stand on Route 812 in rural Oswegatchie in St. Lawrence County. A witness says a white, four-door sedan pulled up to the family's farm stand. The witness then saw someone shove something into the back seat, then get in the back seat. The car left and the two girls were gone.
It's not known if the witness, like the missing girls, was Amish, in which case they'd likely not have a cell phone to immediately contact police.
"The challenge is exactly that. Being rural, they don't have the specific make and model and/or license plate, so they will have that right now as a little bit of a challenge, as well as the missing girls do only speak Pennsylvania Dutch with very little English," says Fical.
Another huge challenge -- there are no pictures of the missing girls.
"And right now, we don't have that specific picture so in the event they take the dresses and put the girls into regular, American-type clothes, the resemblance of these girls may not be the same," says Fical.
The National Center for Missing and Exploited Children is sending out fliers with the girls' description and most updated information -- likely to include a pencil sketch of older sister Fannie Miller, which authorities released Thursday afternoon.
Anyone with any information as asked to call 911 or (866) NYS-AMBER.
Officials with the National Center for Missing and Exploited Children urge parents to always have updated pictures of their children.