Complex sentence: After examination of the things, Begichev decided that the bones belonged to one of the missing Norwegian seamen; however, after Begichev's death, it was presumed that the bones belonged to somebody from Rusanov's expedition.
Split into simpler sentences: After examination of the things, Begichev decided that the bones belonged to one of the missing Norwegian seamen. However, after Begichev's death, it was presumed that the bones belonged to somebody from Rusanov's expedition.