A Florida judge ruled on Wednesday that jurors in the murder trial of George Zimmerman should hear telephone calls the neighborhood watch volunteer made to police in the months before he killed the unarmed Black teenager Trayvon Martin.

"Defense objection to relevancy is denied, the tapes will come into evidence," Seminole County Circuit Judge Debra Nelson said.

Prosecutors say the calls, in which Zimmerman reported what he described as suspicious activity by Black men, demonstrated "profiling" and were key to understanding the defendant's state of mind on February 26, 2012 when he called police to report Martin, minutes before shooting him in the chest at point-blank range.

Defense attorneys have objected to the use of the tapes in the trial, describing the phone calls made between August 2011 and February 2012 as "irrelevant," and contending that they would tell jurors nothing about Zimmerman's thinking on the night he shot the 17-year-old Martin.

At the time of the killing, Zimmerman, 29, and part Hispanic, was a neighborhood watch coordinator in the Retreat at Twin Lakes community in Sanford, Florida.

He has pleaded not guilty to second-degree murder and could face life imprisonment if convicted.