Wildlife officials are currently investigating the cause of death of an 18-foot killer whale that mysteriously washed ashore at Driftwood Beach, on Tomales Point, late last week. “We’re probably not going to know anything for a while,” said Jim Oswald of the Marine Mammal Center, which is handling the investigation alongside the California Academy of Sciences. Oswald said there were blunt trauma wounds to the whale’s head and chest cavities, but that officials could not…