Underscoring the breadth of the crisis facing Adelphia Communications, the company said yesterday that its founder and chief executive, John J. Rigas, had resigned and that it was conducting an investigation into issues raised during the preparation of its 2001 financial statements. Mr. Rigas's son, Timothy, the company's chief financial officer, may resign both his post and his board seat today. Trading in Adelphia's shares was halted yesterday. Adelphia may be delisted, which could lead the company into bankruptcy. Adelphia has $1B in convertible bonds with a covenant that allows holders to exchange them for cash if the company is delisted. Because the company does not have enough cash to cover any such conversion, such demand could force the company to seek bankruptcy protection. Chief Executive Resigns Post as Adelphia Widens Inquiry | 
