Mark O'Mara, the criminal defense attorney representing former neighborhood watchman George Zimmerman, on Friday urged the mother of slain teen Trayvon Martin to admit that her son may have "caused his own death."

O'Mara began his cross-examination of Sabrina Fulton by apologizing for her loss.

"You need to ask a question," Fulton replied.

The defense attorney then tried to throw cold water on Fulton's assertion that it was her son's voice screaming on a 911 call the night he was shot and killed by Zimmerman.

"If it was your son, in fact, screaming as you testified, that would suggest that it was Mr. Zimmerman's fault that led to his death," O'Mara observed. "And if it was not your son screaming, if it was, in fact, George Zimmerman then you would have to accept the probability that it was Trayvon Martin that caused his own death, correct?"

"I don't understand your question," Fulton said. "I heard my son screaming."

"You certainly had to hope that was your son screaming even before you heard it, correct?" O'Mara continued.

"I didn't hope for anything," Fulton insisted. "I just simply listened to the tape."

"I don't meant to put you through this any more than necessary, but you certainly would hope your son, Trayvon Martin, did nothing that could have led to his own death, correct?" O'Mara tried again.

"What I hope for is that this wouldn't have ever happened and he would still be here," Fulton shot back. "That's my hope."