MICHAEL VICK and his family have been threatened lately through social media, as have bookstores where Vick planned to promote his book, "Finally Free." Vick has canceled appearances at three Barnes & Noble locations because of the threats, which have been reported to law enforcement, Vick spokesman Chris Shigas said Monday.

Shigas called the threats, first reported by Tim McManus on Phillymag.com, "very disturbing." Vick has been a lightning rod since he returned to the NFL with the Eagles in 2009 after serving 19 months in federal prison for running a dogfighting operation, but the public furor seemed to abate over the past few years. Shigas said he doesn't know why Vick and his family have aroused fresh vitriol.

"We understand that a lot of people out there will never forgive him," Shigas said. "But at what point do we say a line has been crossed?"

Byron Williamson, president of Worthy Publishing, which published Vick's book, said in a press release: "While we stand by Michael Vick's right to free speech and the retailers' right to free commerce, we cannot knowingly put anyone in harm's way, and therefore we must announce the cancellation of Mr. Vick's book-signing appearances."

One of the Barnes & Noble appearances was scheduled for Exton on March 26, with Vick planning to donate Nike gear to a VFW post. The other two were in Atlanta and in northern New Jersey. "We'll figure out a way to get that [donation] done," Shigas said. "He's going to continue to work in the community. It's just a shame that there's a level of hatred out there."

Shigas said many of the threats have included a racial epithet. "We're confident law enforcement is taking them seriously and will react appropriately," he said.

The Eagles recently reworked Vick's contract, and he is considered the leading candidate to start at quarterback again in 2013.

- Les Bowen