A key witness for defense attorneys in the Casey Anthony murder trial said Friday he did not know the defendant's father, a potential blow to the defense team's argument claiming the witness communicated with Anthony's father around the time of her daughter's disappearance. 

In a hastily organized press conference in front of the Orange County Courthouse Friday, Vasco Thompson, a recently added witness to the defense witness list, adamantly denied knowing George Anthony. 

Casey Anthony, a 25-year-old Orlando mother, is on trial for first-degree murder in the 2008 death of her 2-year-old daughter, Caylee. Prosecutors claim she suffocated the child by placing duct tape over her nose and mouth, while defense attorneys say the girl accidentally drowned in her grandparents' pool and that her grandfather, George Anthony, disposed of the body.

The defense team called Thompson, a convicted felon, to the witness stand Friday, claiming Thompson and George Anthony communicated by cell phone or text message in the days surrounding Caylee's disappearance.

According to a defense filing this week, Thompson was connected to George Anthony through his cell phone records. Defense attorneys claim the two communicated in at least four phone calls on July 14, 2008, a day before Caylee was reported missing by her grandmother, Cindy Anthony. 

But Thompson told reporters Friday, "I have no idea who George Anthony is," saying, "I never talked to him."  

"I don't know him. That number in question, I didn't have that number until February of 2009, " Thompson said. " I don't know why they got me involved in this mess."

George and Cindy Anthony's lawyer, Mark Lippman, told Fox News earlier this week that George Anthony did not know Thompson.

During the press conference Friday, Thompson's lawyer, Matt Morgan, said his client was now a church-going man who paid his debt to society and was being used as a " scapegoat" by the defense team.

Serafin Gomez covers Special Events and Politics for FOX News Channel and is also a contributor to FOX News Latino. Fin formerly worked as the Miami Bureau Producer for Fox News Channel where he covered Latin America. Follow him on Twitter: @Finnygo.

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