the metal fragments found on arlene jensen's body and in her apartment were sent to the forensics lab for testing. under a microscope, scientists could see that the fragments were different shapes and sizes. the surfaces were corrugated and the composition of the metal varied from piece to piece. >> they were made of various types of steel, various grades of steel, various grades of brass. >> the unique shapes and the fact some were hollow were a clear indication of their origin. >> what that means to me is that's a piece of metal which is projected through the air. when it's projected through the air, metal, molten metal, when projected through the air is cooling very, very rapidly. with the air current as it goes through the air it dries to a soccer ball round shape. >> so investigators knew the killer was probably a machinist, someone who worked with metal at high heat on a lathe.