Docei Is a Demon?

In Acts 16, we were met by a slave girl who had a spirit of divine on and brought her owners much gain by soothsaying. She followed paul and us crying, these men are servants of the most high god who proclaim to you the way of salvation. In second corinthians 11, saint paul warns us that the devil himself masquerades as an angel of light. So one of his cronies could certainly masquerade as a sitter's dead brother. And in first john four, saint john warns us, beloved, do not believe every spirit, but test the spirits to see whether they are of god.