His North Carolina based spokesperson, Chris Shigas, says the threats have been made on social media sites and phoned into the bookstores.
In one threat Vick is told, "We should push your daughter into a pool with a battery."
"He's obviously concerned about it. He's concerned about it. You know, Mike is committed to working with the community, to talking with kids, to getting them to make positive decisions in their lives and he's going to continue to do that," Shigas said.
Vick just completed one book signing in Charlotte, but cancelled appearances in Atlanta, North Jersey, and Exton.
In another expletive filled threat, Vick was told, "When I see you, I'm going to bash your [expletive] head in."
The threats are nothing new for Vick, who served time on dog fighting charges. Protests followed when he was signed by the Philadelphia Eagles.
His spokesperson says the threats dwindled as time went by, but then got increasingly violent this past week.
"We had an uptick in the number of threats that were made against Michael Vick, as well as his family. The threats were made against the bookstore property, as well as bookstore employees," Shigas said.
Vick's spokesperson says authorities are investigating.
Number 7's appearances will be put on hold as the investigation develops.
Shigas does say Vick has a message to the local fans.
"He feels the love of Philly everyday and appreciates that and he just wants his fans to know that he'll continue engaging in the community and trying to make the community a better place," Shigas said.
During his scheduled March 26th Exton appearance, Vick was set to donate Nike gear to the local VFW. Shigas said that will happen, regardless, one way or another.