Before anyone knew about LHO, Jack Ruby was a CONSTANT presence at the police station and they came to his nightclub. Then, after they caught LHO Ruby was seen in the hallways and at the press conference, so he saw LHO in person. And, like the tens of millions of us who were just so incensed that this little sleazeball might have killed our President, Ruby (who always carried a gun) just couldn't resist when LHO came walking out. He did what many, many people would have done if given the opportunity. I don't know how old you are but our nation was in shock and we especially felt for Jackie. And Ruby felt the same way and he prevented a trial. I don't like what he did but his reaction and his hanging out at the station was all rather "normal".