Federal investigators, responding to a Freedom of Information Act request by WSB-TV's Scott MacFarlane, have revealed Vick personally killed at least seven of his fighting dogs by hanging or drowning. They also revealed Vick failed police polygraph tests in which he denied killing animals. And the federal paperwork said Vick decided to start his dogfighting ring just days after being drafted by the Atlanta Falcons in 2001.

SLIDESHOW: Exclusive Look Inside Vick's Dogfighting House

This information could influence the punishment Vick receives tomorrow, when he enters a guilty plea to state dog killing charges in Sussex, Va. Vick was thought to have secured leniency by offering to a guilty plea but the new information puts his future in doubt yet again.

Michael Vick is back in Virginia to face state dogfighting charges in a court appearance this week.

Hopewell Regional Jail Superintendent Darnley Hodge said the former NFL star is being held in protective custody. Hodge said Vick is isolated from the rest of the jail's 1,200 inmates to avoid disruptions but is being treated like any other prisoner.

Hodge said Vick arrived Thursday from the federal penitentiary in Leavenworth, Kansas, where he's serving a 23-month sentence for a federal dogfighting conspiracy.

Previous Stories: November 22, 2008: Vick Put Family Pets In Ring Against Pit Bulls November 21, 2008: Vick Moved From Federal Prison November 14, 2008: How Michael Vick Spent $17.7 Million In Two Years November 14, 2008: Vick's Former Dogs Featured On Wine Labels October 21, 2008: Vick To Enter Plea On State Dogfighting Charges September 3, 2008: $800K, 1 Year Later: 4 Michael Vick Fighting Dogs Saved July 8, 2008: Michael Vick Files For Bankruptcy