I always felt that Zardari knows the right people or knows how to bribe the right people to get out of trouble or to fabricate or destroy evidence. It is no surprise that everytime a case is tight against him, a key witness or suspect or someone in the prosecution team or even the judge ends up getting murdered.
Even when he was incarcerated from 1996 to 2004, it wasn't as if he was in full blown jail conditions that a common citizen has to endure, he was getting luxuries, air conditioned facilities, female visitors and other amenities.