Madeleine's parents pain at losing her was 'multiplied 100 times' by police chief's book, court hears as her father expresses disappointment he couldn't give evidence Gerry's sister says parents in 'purgatory' over claims they were involved Kate and Gerry McCann's pain over the disappearance of their daughter was 'multiplied 100 times' by a book by a former Portuguese police chief, a court has heard. Gerry McCann's sister Trish Cameron said he and wife Kate had been left in 'purgatory' by the disappearance of Madeleine and claims that they were somehow involved. Speaking at the libel trial of former police chief Goncalo Amaral, Mrs Cameron said the publication of his book in 2008 and a TV documentary based on it the following year caused the family to be 'vilified' and 'demonised'. And she said Madeleine's twin siblings Sean and Amelie, now eight, told their parents that comments were made by fellow pupils at their school. She told the court: 'My brother and sister-in-law live in purgatory because they have no end and they are looking for the truth. 'They would like an end but there is no end because they don't know what's happened.' The McCanns say the former detective's claims in the book The Truth Of The Lie, including suggestions that they hid their daughter's body after she died in an accident and faked an abduction, damaged the hunt for Madeleine and exacerbated her family's anguish. If successful in the legal action, brought against him, his publisher, and the makers of the documentary, the family stands to gain around £1 million in damages. Mrs Cameron, whose voice cracked as she described the effect on her family by the publication of the book, said: 'They were vilified in this book so their distress was multiplied 100 times. This pain was felt by all of their family because we still have a missing child and we knew that what is in there is not true. Earlier, Gerry McCann had arrived at the court in a bid to give evidence against the disgraced police chief, but later expressed his disappointment that he was not able to take part in the proceedings. 'Disappointed,' McCann told reporters as he left the courthouse, 'but you know, we'll keep going.' It is not clear why he was not able to give evidence.