On 28 May 2004, Father Andre Bohas msc was appointed Diocesan Postulator to undertake responsibility for the preliminary investigation. At the ad limina visit of the bishops from Southern Africa in June 2005, Bishop Slattery met with a small delegation at the Sacred Congregation for the Causes of Saints where he received helpful advice regarding how to proceed with the investigation. To prepare for his work as Diocesan Postulator, Father Bohas was sent to Rome in August 2005 for a 4-month course conducted by the Sacred Congregation. His work as Diocesan Postulator involved finding and interviewing people who knew Benedict intimately, beginning with members of his own family as well as other people who had worked closely with him in the parish or in the field of education. This preliminary investigation convinced Bishop Slattery that they were dealing with a very special person who could possibly have died a martyr for the faith.
On completion of this preliminary enquiry in 2007, Bishop Slattery wrote to the Apostolic Nuncio, Archbishop James Patrick Green, on 12 September informing him of Benedict Daswa and the steps already undertaken by the diocese regarding the possible presentation of his cause for beatification. In his reply of 4 October 2007, Archbishop Green who was most encouraging, suggested that Bishop Slattery present the findings of the preliminary investigation to the January 2008 Plenary Session of the SACBC. The purpose was to explain at first-hand the steps already taken, and to hear the opinions of the bishops concerning the cause. As the bishops were enthusiastic in their support, the President, Archbishop Buti Tlhagale omi, on behalf of the Conference, wrote a formal letter of full support to Bishop Slattery on 6 February 2008 in which he quoted the resolution taken by the Conference. Encouraged by this support, Bishop Slattery wrote to the Prefect of the Sacred Congregation for the Causes of Saints in March 2008, giving an outline of the preliminary Inquiry and its results.