Of course, any politician, including those running the top echelons of government, should not be immune from prosecution. Perhaps corruption that is so rampant would be far less prevalent if these people truly understood that they were responsible and would be held accountable by the same laws that govern everyone else.
Heads of states and other officials should not be given immunity. With immunity they will have no care for others and if they commit a serious crime we are powerless to do anything about it. The better option is to find a way for them to have special priviledges but not immunity.