A former associate of Bernard Madoff avoided prison on Thursday for his role in perpetuating the fraudster’s massive Ponzi scheme because of his extensive cooperation with prosecutors. Paul Konigsberg, 79, a lawyer and accounting firm executive, pleaded guilty in June 2014 to charges of conspiracy and falsifying books and records. At the time, his cooperation deal was seen as a signal that prosecutors were still pursuing a criminal case against Madoff’s son, Andrew, who died of cancer three months later.