text: The party is conducting an inquiry into the death of youth activist Elliott Johnson, 21, and has taken more than 40 witness statements, it said.
  Tory chairman Lord Feldman is a witness and the inquiry will last into 2016.
  Cabinet minister Grant Shapps resigned over allegations he failed to act on claims of bullying while co-chairman.
  Claims of bullying have centred around Mark Clarke - a Tory activist who ran the party's RoadTrip campaign, bussing election volunteers around the country.
  Before his death in September, Mr Johnson had complained to Conservative Central Office that Mr Clarke had threatened to destroy his career. He also named Mr Clarke in a letter found by his parents after his death.
  Mr Clarke has rejected allegations of bullying, sexual assault and intimidation. He has since been expelled from the party.
  On Saturday, Mr Shapps resigned as international development minister, saying the "buck stops with me" regarding issues while he was party co-chairman.
  The party has launched an independent inquiry into the allegations, saying it remains "absolutely determined" to establish the truth of the events surrounding Mr Johnson's death.
  It says an independent lawyer will also prepare a report on the allegations.
  The party has urged anyone with information relating to events surrounding the death of Mr Johnson, or the activities of Mr Clarke, to get in touch with it "as soon as possible".
  It comes as Mr Johnson's father has called on Lord Feldman - who was co-chairman with Mr Shapps until May and now holds the role alone - to also resign.
  Lord Feldman is "a witness" in the party's investigation but "is not otherwise participating in the process", the Tories added.
  The Tory peer retains the "full confidence" of Prime Minister David Cameron, Downing Street has said.
target: The Conservative Party has urged anyone with information about claims of bullying within a Tory youth wing to get in touch with its investigation.