The name of the expert on paranormal activity is Leek, the reverse of paranormal expert and author of the novel on which this movie was based, John A. Keel.
This movie is based on actual events that occurred between November 1966 and December 1967 in Point Pleasant, West Virginia.
Lakeshore Entertainment cut two million dollars out of the budget just days before shooting began. Director Mark Pellington was furious, having vowed not to make the same concessions that plagued his previous movie, Arlington Road (1999).
Contrary to popular belief, the Mothman wasn't originally described as a moth-like creature by the witnesses. At the time, the creature was described as half-bird and half-man. They also claimed that the creature had feathers and would make screeching noise. Many skeptics have attributed sightings of Mothman to bird not native to Point Pleasant, like a crane or a heron. Locals in Point Pleasant take it to be a snowy owl which got lost and ended up in the area, frightening locals who'd were unfamiliar to the bird. Local hunter Ace Henry shot and killed such an owl in 1966 after which the initial wave of sightings stopped. Said owl was stuffed and in on exhibit at the Mothman Museum in Point Pleasant who identifies it as "the body of Mothman".
The scene where Indrid Cold is seen for the first time in full wasn't done with CGI. Bill Laing was simply shot in blurred vision.