While ago back I had chat with one of client who was Jehovah witness and In our discussion he denied Holy Spirit as Person but according to their belief its an influence/power/etc.
Looking through Scripture and trying to understand who is Holy Spirit? considering
Acts 1:7-8 And he said unto them, It is not for you to know the times or the seasons, which the Father hath put in his own power. But ye shall receive power, after that the Holy Ghost is come upon you: and ye shall be witnesses unto me both in Jerusalem, and