SANFORD, Fla. – George Zimmerman testified that he was driving to a doctor’s appointment when he noticed he was being pursued by a vehicle whose driver later pulled up, exchanged words and fired one gunshot at him that missed.

“I heard a bang and my ears started ringing,” Zimmerman, 32, told the jury in the attempted second-degree murder trial of Matthew Apperson, 37. The trial opened Tuesday in the Seminole County Courthouse.

The incident on May 11, 2015 was not the first encounter between Apperson and Zimmerman, the former neighbourhood watch volunteer who fatally shooting unarmed teenager Trayvon Martin in 2012. Apperson alleged in September 2014 that Zimmerman threatened him in a road-rage encounter, but did not press charges at the time.

During the later exchange, Zimmerman testified that Apperson asked whether he remembered him and said he didn’t press charges earlier “because I wanted to kill you myself.”

Apperson’s attorney, Michael LaFay, said that Zimmerman was the aggressor and brandished a gun in both incidents, but prosecutor Stewart Stone said there was no way Apperson could have seen a gun through the tinted windows of Zimmerman’s car.

The trial was scheduled to continue Wednesday.

In the Martin case, Zimmerman claimed self-defence and was acquitted of charges in the shooting, a verdict that sparked protests and a national debate about race relations. Martin was black and Zimmerman identifies as Hispanic.