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George Zimmerman enters not guilty plea

George Zimmerman, who was arrested and charged in the shooting death of Trayvon Martin, is seen in this booking photo on Wednesday, April 11, 2012. (Seminole County Sheriff`s Office)

April 24, 2012 12:00:00 AM PDT
George Zimmerman entered a written plea of not guilty on Tuesday to second-degree murder charges in the shooting death of Trayvon Martin.

Zimmerman's attorneys requested that his appearance be waived at his arraignment, which had been scheduled for May 8.

Meanwhile, the police chief remains under scrutiny for not charging Zimmerman immediately after the unarmed teen's death. The lack of an arrest led to protests across the country and spurred a debate about race and laws of self defense. Zimmerman maintains that he acted in self defense.

Chief Bill Lee handed in his resignation on Monday, just hours after Zimmerman was released on bail, but Sanford city commissioners rejected the resignation.

"The city commission spoke," city manager Norton Bonaparte said. "They were not ready to have the resignation. So we'll move forward."

The commissioners said they wanted to wait for the results of a federal investigation to take action. The U.S. Department of Justice is expected to make a thorough analysis of the police department's handling of the Feb. 26 killing.

The Associated Press contributed to this report.