Between 03:00 and 06:10 the following morning, forensic scientist Frank Skuse conducted a series of Griess tests upon the hands, fingernails and belongings of the five men arrested at Heysham Port, to determine whether any of the men had handled the explosive nitroglycerine. He concluded with a 99% degree of certainty that both Patrick Hill and William Power had handled explosives, and remained uncertain as to the test results conducted on John Walker, whose right hand had tested positive, but whose left hand had tested negative. The test results upon Hunter and McIlkenny had been negative.