As federal investigations continue around him, pressure is increasing on Rep. John Murtha (D-PA), including a call for him to quit his post atop the powerful House Defense Appropriations panel. Federal investigators are reportedly probing at least four organizations whose financial livelihoods have been closely tied to Murtha. Murtha has not been named as a target of any of the probes, although his name has come up in interviews with the investigators, according to sources and news reports. The PMA Group, a now-defunct lobbying firm, is being probed reportedly for suspicions of campaign finance fraud – possibly using so-called “straw donors” to funnel thousands to lawmakers’ war chests, possibly including Murtha’s. Its former chief, Paul Magliocchetti, is a former House aide described as close to Murtha who won millions in earmarks for his clients from the veteran Pennsylvania lawmaker. Meanwhile, other investigators are trying to determine if Kuchera Defense Systems and an affiliate “inflated its payroll in order to run up higher expenses in federal contracts,” the Pittsburgh Post-Gazette reported over the weekend. The Pennsylvania-based firms have pocketed a significant chunk of federal defense money, as Murtha has proudly announced in numerous press releases on his House Web site. The Feds are also investigating the Electro-Optics Center at Penn State University, a research facility Murtha helped found which has doled out tens of millions in Pentagon research dollars, often to lobbying clients of the Murtha-linked PMA Group. In addition, a federal probe into another Murtha-linked defense research center, Concurrent Technologies Corporation, was reported last year, when the FBI issued subpoenas for information related to several Pentagon contracts the organization had won. The Washington Post has dug into a defense subcontracting firm owned by Murtha’s nephew that it depicted as doing little work for millions in defense money. And at least one other Murtha beneficiary, Argon ST, has been reportedly talking to federal agents, although the company says they are neither a target nor a subject of an investigation. Murtha, and all the players under investigation who have commented to the media, have denied any wrongdoing. The federal probes do not appear to be directly connected or controlled by a single office, agency or prosecutor, but instead involve various combinations including the U.S. Attorney for the Western District of Pennsylvania, the Defense Criminal Investigation Service, the Justice Department’s Public Integrity Section, and the FBI. With friends like these, the saying goes. Unfortunately for Murtha, the swirl of scandal has elevated calls for his ouster, at least from his Defense Appropriations perch. In a Huffington Post column Friday, one of D.C.’s most outspoken clean-government advocates, Melanie Sloan of the group Citizens for Responsibility and Ethics in Washington, said it was time for Murtha to leave that subcommittee.