Who Is The Liar?

I think that most people would rather know the truth and deal with it than be lied to and never know. That is what happened at my office the other day. Someone went into the computer system and changed a default, locking other people out. They thought that no one would notice. Too bad for them that I did. There were only two possible suspects. One was the new doctor and the other, her old assistant. Her assistant is now considered an employee of my office, so my boss is also her boss. Now the plot thickens. When I told my boss about the computer situation, she questioned the doctor, who swore that she did not do it. She claimed that she is not a computer person and would have no idea how to change things. My boss then questioned the assistant who also claimed that she would have had no idea how to do it. This girl is a computer wiz and already told me that she knows how to work the new system. So now we have two suspects, each one claiming innocence. My boss is angry because she is being lied to. By Monday, she wants an answer and for someone to undo what they did.