From The New York Times:

He said the dispatcher told him not to follow Mr. Martin so he was returning to his vehicle when "the suspect emerged from the darkness and said 'You got a problem?'" 

Mr. Zimmerman said he responded, "No," but said that Mr. Matin told him, "You do now." Mr. Zimmerman said that when he tried to use his cellphone to dial 911 again, that Mr. Martin punched him in the face, causing Mr. Zimmerman to fall "backwards onto my back." 

"The suspect got on top of me," Mr. Zimmerman wrote in the statement. "I yelled, 'Help' several times." 

Mr. Zimmerman wrote that Mr. Martin had cursed at him while telling him to be quiet before he grabbed Mr. Zimmerman's head and slammed it into the sidewalk several times. 

"My head felt like it was going to explode," Mr. Zimmerman wrote, adding that he continued to scream for help. Mr. Zimmerman said that as he tried to slide from underneath Mr. Martin that the teenager "covered my mouth and nose and stopped my breathing." 

Next, Mr. Zimmerman wrote, "I felt the suspect reach for my now exposed firearm and say, 'Your gonna die tonight," while calling him an obscene name. 

"I unholstered my firearm in fear for my life as he had assured he was going to kill me and fired one shot into his torso." 

Mr. Zimmerman then wrote that Mr. Martin sat up and said, "You got me."

The new evidence emerging of Zimmerman's implausible narratives is very damaging to his defense. If his relatives want to go around telling the media ridiculous stories of the type seen only in bad action flicks (like "after I shot him, he said 'you got me'"), that doesn't actually hurt him at trial, because Zimmerman isn't responsible for what his family members may claim. But now that we know he himself was telling these unbelievable stories to the police, that makes it pretty likely the jury will hear about them, and view his newer, more plausible story with a jaundiced eye.