The publishing house that produced The Lost Boys of Bird Island, the controversial book co-authored by Mark Minnie, says he indicated the book was "only the beginning".In a statement released on Tuesday evening, Tafelberg Publishers said Minnie suggested he had successfully followed up several leads in Port Elizabeth during the past week and was determined to reveal further evidence."He was excited about the publication of the book and the disclosure of allegations which, according to him, had been covered up for 30 years. He said that the book was 'only the beginning' of the process to have justice prevail for the [alleged] victims whose stories are told in the book," the publisher said.Tafelberg said their last contact with Minnie was on Sunday night.ALSO READ: Authors of book claiming that Magnus Malan was a paedophile feared for their lives"But he had been out of reach since Monday morning. His cellphone had been switched off and he hadn't responded to emails. In the week preceding his death, Minnie had said nothing to Tafelberg to indicate that he might harm himself."The publishing house added that Minnie looked forward to Cape Town's Open Book Festival where he, together with his co-author Chris Steyn and journalist Marianne Thamm, were going to discuss the book.Steyn said she was shattered by Minnie's unexpected death and stood by every word in the book."Mark said it was our task to have justice prevail for the victims. He would have wanted me to continue and that is exactly what I'll be doing."The publisher said that Yasmin Sooka, executive director of the Foundation for Human Rights, contacted Steyn saying the foundation "wants to take up the matter on behalf of the boys of Bird Island"."Mark will never know about this, but it is exactly what he hoped for. It is too late for him, but not for the victims," she said.Minnie's body was found on the outskirts of Port Elizabeth on Tuesday morning. Police confirmed that they found what was thought to be a suicide note earlier in the day. They also confirmed an inquest was opened to investigate why a firearm was used that was not his.READ: Mark Minnie did not use his own firearm in alleged suicide – policeHis book details allegations that former apartheid minister Magnus Malan was part of a paedophile network.News24 previously reported that the book detailed how three former National Party ministers, including one who is still alive, were allegedly central figures in a paedophile ring that operated during apartheid.Investigations into Malan – as well as John Wiley (the former Minister of Environmental Affairs) and another former minister, who was considered a possible successor to then president PW Botha and who is still alive – were halted by the police, and the investigating officer was hounded from service in the 1980s.These and other explosive allegations are contained in the book by Minnie, a former police officer, and Steyn, a former investigative journalist.According to the book, Malan, Wiley and the other minister were involved, along with disgraced Port Elizabeth businessman John Allen, in ferrying coloured minors to Bird Island, in Algoa Bay near Port Elizabeth, where the children were molested and forced to satisfy the older men's sexual fantasies.Malan died in 2011, while Wiley and Allen's deaths in 1987 were recorded as suicides.