In November 1997 at a conference in Princeton University Hata was confronted by Iris Chang, author of the book "The Rape of Nanking", who asked him why he doubted the testimony of Japanese POWs who had stated that hundreds of thousands of Chinese were killed in the atrocity. When Hata replied that torture and coercion of Japanese POWs made their testimony unreliable Chang walked out and the audience became unruly, shouting Hata down and yelling insults at him. The moderator Perry Link barely kept the situation under control. In the wake of this incident, similar disruptions by Chinese students who disagreed with his death toll estimate prevented Hata from speaking at a number of universities that he visited. Bob Wakabayashi of York University argues that Hata became more strident in his tone following these attacks, once calling it the "Nanking industry" in comparison with Norman Finkelstein's "Holocaust industry". In the 1980s Hata had stated that the death toll was 38,000 to 42,000 while holding out the possibility that it might have been as high as 60,000, but when he wrote the second edition of "Nankin Jiken" in 2007 he indicated that 42,000 massacred was the maximum possible and that the true number might have been lower.