A Florida gun collector has pleaded not guilty to a murder charge alleging that he opened fire on a car full of unarmed teenagers, killing one, in an altercation that police say stemmed from loud music.

Michael David Dunn, 45, acted "as any responsible firearms owner would have," his lawyer said of the Friday evening incident at a gas station outside a convenience store in Jacksonville, Fla.

Dunn and his girlfriend were in Jacksonville for his son's wedding when they pulled up in their car next to the teens. Police allege that while the girlfriend was in the store, Dunn told Jordan Russell Davis, 17, and his three friends to turn down their music.

"It was loud," Jacksonville homicide Lt. Rob Schoonover said of the teens' music. "They admitted that. That's not a reason for someone to open fire."

After an exchange of words, Dunn began shooting with a handgun, Schoonover said.

"Nobody else in that vehicle was struck; it was just our victim [Davis], which was lucky because the vehicle was shot eight or nine times," Schoonover said.

Davis was in the back seat and was struck twice, reported The Orlando Sentinel.

Dunn and his girlfriend drove off and spent the night at their hotel, according to Schoonover, but witnesses took down his license plate number. Police arrested him Saturday morning at his home in Satellite Beach, Fla., on one charge of murder and three charges of attempted murder.

"His side of the story is he felt threatened and that is the reason he took action," Schoonover said.

On Monday, Dunn — a gun collector who shot at local gun ranges, according to authorities — pleaded not guilty in Brevard County court, with his attorney describing his actions as self-defense.

Additional details at: http://usnews.nbcnews.com/_news/2012/11/28/15513847-florida-man-pleads-not-guilty-to-shooting-teen-to-death-over-loud-music?lite