Who is this boy?

Investigators in Maine continue to ask this question two days after discovering the body of an unidentified four- or five-year-old boy on the side of a rural road.

Authorities have received more than 100 tips about the child, but Maine State Police Lt. Brian McDonough told ABC News that his agency is no closer to identifying the boy than they were when they found the child under a blanket on a remote road in South Berwick at around 5 p.m. on Saturday.

"Somebody has got to miss this child. He's a nephew of somebody, a son or grandson of somebody. ... It's just been very, very frustrating that we haven't gotten any leads, significant leads, in identifying this child," McDonough said.

Police say the child's death is suspicious.

The boy is described as having short, dirty blonde hair and blue eyes. According to police, the child is about three feet, eight inches, weighs 45 pounds and still has his baby teeth.

He was found wearing a gray camouflage hooded sweatshirt, tan pants and a dark blue short-sleeved shirt featuring the words "Aviator Series," CNN reports.

Making matters more complicated, no child matching that description has been reported missing in Maine, New Hampshire or Massachusetts.

Maine State Police have released a computer generated image of the boy, hoping someone will recognize the child.

Authorities are currently investigating reports from witnesses who spotted a woman driving a blue Toyota Tacoma pickup truck with an extended cab and a covered bed near the site where the body was discovered on Saturday morning.

Authorities urge anyone with information about the child or the pickup truck to call Maine State Police at (207) 657-3030.

WATCH: