Was told by tower controllers to maintain 6500 until 5 mile final contollers then told some 90 year old weekend warrior to follow me. after passing 5 mile final i decided for some reason not to descend right away. At about 4 miles I started a slow descent. At which time the controllers started freaking out on the old man to slow down cause he is overtaking me and is not about .5 miles behind me. The old man said ok and that he was still looking for me. At this time contollers asked me if I can see him behind me and of course I can't. I am still descending and the controllers then tell the old man to do a 360 for spacing and he says he will. At this time I just happen to look out the window and down and about 50 feet underneath me is the plane so I imediately started a climbing right turn and infrom tower. Then the contollers freak out on him about not doing the 360 and when he gets on the ground......... he got the number. So even when you are in the hands of contollers shyt can happen!