The head of a congressional panel is vowing to subpoena more people about why the pensions of salaried retirees of bankrupt auto-parts supplier Delphi were cut, while those of other auto industry retirees were not. Republican Congressman John Mica of Florida chairs the House Subcommittee on Government Operations. He spoke in Dayton yesterday. The more than 20 thousand retirees are suing to have their full pensions restored. The pensions were cut when the company released its obligations to a federally backed insurer while under bankruptcy protection in 2009.