The Famous Forest Rose Apparition

Came across these photos taken at Forest Rose Cemetery in Lancaster, Ohio, back in July 2005, and I'm curious what everyone thinks.

According to the Ohio Exploration Society, one of their members photographed what appears to be a figure standing on a hillside above a mausoleum. They claim there were only four members at the cemetery that night, and all four were accounted for when the picture was taken.

Here's what makes me skeptical, though. Apparently, the camera's shutter was open for around 20–30 seconds. Couldn't someone walking through the frame during that time create this exact effect?

I'm not saying the photos are fake, but I'm definitely not convinced it's a ghost either. The figure does look strangely human, which makes it interesting.

What's everyone think? Actual apparition, someone caught in a long exposure, or something else entirely?