A worker disassembles a car at an auto shop in Wareham, Massachusetts. The federal watchdog for corporate bankruptcies joined a creditor’s demand for an independent investigation of the troubled auto-parts supplier First Brands Group, which has admitted it can’t find $2.3 billion related to off-balance sheet financing deals. Most Read from Bloomberg The US Trustee argued in court filings that “serious allegations of fraud, dishonesty, incompetence, misconduct, or mismanagement,” justifies a quicker-than- ...