Conversation so far:
Who was Helen Duncan?
Helen Duncan was a Scottish medium best known as the last person to be imprisoned under the British Witchcraft Act of 1735.
How was Harry Price connected to Helen Duncan?
£50 was paid to the medium Helen Duncan so that she could be examined under scientific conditions. Price was sceptical of Duncan and had her perform test séances.

Question: Did he invesitgate other things related to Helen?
Self-contained rewrite: Did Harry Price investigate other things related to Helen Duncan besides having Helen Duncan perform a number of test séances?