Prosecutor: Martin killed because of bad assumptions

Trayvon Martin died because George Zimmerman wrongly assumed he was a criminal, prosecutors on Thursday told a Florida jury in closing arguments in the neighborhood watch volunteer's second-degree murder trial.

After prosecutors finish, defense lawyers are due on Friday to make their closing statements in the case, which has captivated and polarized much of the U.S. public. The jury is expected to start deliberations Friday.

"A teenager is dead," Florida state prosecutor Bernie de la Rionda told the jury. "He is dead through no fault of his own. He is dead because another man made assumptions. Because his assumptions were wrong, Trayvon Benjamin Martin will no longer walk on this Earth."

Earlier on Thursday, Seminole County Judge Debra Nelson gave jurors the option of convicting Zimmerman of the lesser charge of manslaughter.

However, in a victory for Zimmerman, Nelson denied a prosecution request to add a second option of third-degree felony murder based on child abuse.

Martin, at 17, was a minor. Prosecutors wanted the sequestered, all-female jury to have the option of choosing the lesser offense, which still carries a potentially lengthy sentence.

Zimmerman could be sentenced to life in prison for second-degree murder and up to 30 years for manslaughter.