With no explanation, label text_A→text_B with either "DON'T KNOW", "NO" or "YES".
text_A: On 25 May 1997, Bohumil Šole, a scientist who claimed to have been involved with inventing Semtex, committed suicide at a spa in Jeseník by blowing himself up with explosives. Šole, 63, was being treated there for psychological problems. While it was unclear what explosives were used in the immediate aftermath, a forensic investigation discovered that he had constructed a crude, yet effective, pressure-cooker bomb. Twenty other people were hurt in the explosion, while six were seriously injured. According to the manufacturer, Explosia, he was not a member of the team that developed the explosive in the 1960s.
text_B: Given the amount of reliable evidence (or lack thereof) surrounding the explosion, is it possible (however unlikely) that Bohumil Šole's death could have been a tragic accident rather than a deliberate act?
NO.