Bankrupt retailer Kmart Corp has suspended severance payments to several former executives as part of an investigation into the way the company was run under former chief executive officer Chuck Conaway. The investigation is part of an accounting probe started in January and focuses on what the company called the "stewardship" of Kmart by members of its former management team. Concern was raised after an anonymous letter, claiming to be from employees, was sent to Kmart voicing concerns about accounting irregularities and other issues.