use of Linux may infringe a copyright they hold on the original UNIX source code. They say that the Linux kernel, the core of the operating system contains copyrighted SCO source code. In this letter they also announce the suspension of their own Linux-related activities. July 2003 The SCO Group files an amended complaint. August 2003 SCO announces that they intend to issue invoices to companies using Linux. In Red Hat v. SCO, Red Hat files suit in the United States District Court for the District of Delaware asking for a permanent injunction blocking SCO from asserting that Red Hat infringed on SCO's intellectual property with their Linux product. IBM files its counterclaims, alleging that SCO has violated the GPL, several patents, and the Lanham Act by falsely accusing IBM of violating SCO's IP rights. September 2003 SCO CEO, Darl McBride, writes an open letter to the free software community. In this letter he accuses the free software community of being responsible for recent DDoS attacks on the SCO website and once again asserts that Linux violates SCO's intellectual properties. IBM files amended counterclaims, including a claim of copyright infringement. October 2003 BayStar Capital and Royal Bank of Canada invest $US50 million in SCO to support the legal cost of the SCOsource program. SCO announces that it would not attempt invoicing Linux users after being threatened with mail fraud. December 2003 SCO sends a letter to all Unix licensees asking them to certify certain questions regarding the use of Linux. SCO sends a letter claiming ownership of the Linux ABI code. January 2004 SCO sends a letter to the United States Congress, raising issues such as the economics of open source development and the legality of the GPL. In, SCO v. Novell, SCO files slander of title suit against Novell. February 2004 The SCO Group becomes the target of the Mydoom computer worm, which was programmed to launch a denial of service attack on the company's website beginning on February 1, 2004. The Group has also been the subject of a Google bomb campaign. Google returns SCO's website as the number one hit for the phrase "litigious bastards." SCO files a second amended complaint against IBM. It drops the trade secret claims, but adds claims of copyright infringement. March 2004 In SCO v. AutoZone, SCO files suit against AutoZone in Nevada state court. In SCO v. DaimlerChrysler, SCO files suit