Standing Firm: Michael Vick Refuses To Hide After Receiving Death Threats.

Despite having served 18 months in federal prison and losing millions of dollars in salary and endorsement deals following his 2007 conviction for running a dogfighting operation, some people refuse to let Michael Vick live his life in peace.

Since his May 2009 release from federal custody the Philadelphia Eagles quarterback has been a model citizen by all accounts, but he recently had to cancel a book tour to promote his autobiography "Finally Free" after "credible threats" were called into several Barnes & Noble Booksellers and an independent bookstore in New Jersey.

"It is disturbing that a few extremists would threaten Vick's family and store employees," said Vick's spokesman Chris Shigas. "Michael Vick has millions of fans and has countless letters from teachers thanking him for inspiring students to make positive change."

Despite the death threats, Vick refuses to hide.

According to TMZ, the NFL star will continue giving back to the community by working with the Veterans of Foreign Wars organization and Team Freedom Outreach (recreation and visitation programs for youth detention centers).

"Mike is committed to helping make his community a better place," Vick's rep says. "[He] is determined to continue his work with charity and helping others."