The Horror Expert by Frank Belknap Long

whose knowledge of horror, the occult, and strange phenomena draws him into a disturbing situation where ordinary explanations no longer seem sufficient. What begins as an investigation gradually becomes more threatening as mysterious events, suspicious behavior, and disturbing clues suggest that something far more sinister may be involved.
As the mystery develops, the characters are forced to question what is real and what may be the product of fear, deception, or forces beyond normal understanding. Long builds tension through uncertainty, shadowy surroundings, unusual discoveries, and the growing feeling that danger is always close.
Rather than relying only on sudden shocks, the novel creates horror through atmosphere and suggestion. The fear comes from not knowing whether apparently supernatural events have a rational explanation—or whether the impossible may actually be happening.
Frank Belknap Long, known for his contributions to weird and supernatural fiction, combines elements of the detective story with the darker traditions of cosmic and psychological horror. The result is a suspenseful tale in which investigation and reason must confront events that seem to resist logical explanation.