Jury selection begins today in the Miami, Florida murder trial of Derek Medina, 33, who admits he killed his wife Jennifer Alfonso, 27, in August 2013 at their home. He then posted photos of her body on Facebook. Medina says he killed her in self defense. Medina’s famous Facebook posting included this statement: “I’m going to prison or death sentence for killing my wife. Love you guys. Miss you guys. Take care. Facebook people you’ll see me in the news.” Medina has never denied shooting Alfonso several times but now says it was because she came at him with a knife. He says he was able to disarm her. When it comes to self-defense, so long as the threat is no longer there, then deadly force should not be used. So, if he disarmed her (and, according to one report,…