Through Torchwood, Howarth acquired some alien tissue samples. Exposure to samples provoked a primal fear response in patients. His project was to create hybrid DNA strand for Special Forces applications. Most subjects died in testing. One test subject known as "the Chimera" survived and escaped. Howarth faked his own death, providing a body and switching his DNA sample on Torchwood's records to cover his tracks.
Before Howarth escaped he created a computer analysis program to find the combination of drugs to surpress the Chimera's alien DNA. To see the results, Howarth needed to access Torchwood's mainframe, and sought out Torchwood Three.
The team at Torchwood Three cottoned onto Howarth's deception after they were attacked by the Chimera. Howarth told them the truth about the Chimera shortly before the Hub was attacked by it. Howarth was killed by the Chimera seconds before Toshiko Sato administered the surpressant. (COMIC: The Legacy of Torchwood One!)