The Brevard County man charged with fatally shooting a 17-year-old boy after an argument over loud music testified Tuesday that he thought he saw the barrel of a gun from a neighboring vehicle pointed at him and that he feared for his life before firing his weapon.

Michael Dunn said he tried to de-escalate the confrontation with three teens in a neighboring SUV outside a Jacksonville convenience store in November 2012.

"I couldn't believe what I was seeing and hearing," Dunn said.

Dunn is charged with first-degree murder. He has pleaded not guilty and says he acted in self-defense when he fatally shot 17-year-old Jordan Davis of Marietta, Ga., outside a Jacksonville convenience store in 2012.

The defense rested its case Tuesday, and then prosecutors called Dunn's fiancee back to the witness stand. Rhonda Rouer contradicted Dunn's assertion that he had told her he had seen a gun in the teens' SUV.

In his testimony, Dunn told jurors he was in Jacksonville with his fiancee to attend his son's wedding. He had brought along on the trip his 7-month-old dog, and at one point in testimony he wiped away tears when talking about his fiancee and dog.

Dunn said he and his fiancee went to the convenience store after the wedding for wine and chips. He said he pulled into a spot next to an SUV where music with a "thumping" bass was playing.

"It got really loud," Dunn said. "My rear view mirror was shaking. My eardrums were vibrating. It was ridiculously loud."

Dunn said he asked the three men in the SUV to turn down the music and they turned it off. "I said, `Thank you,'" Dunn said. But soon afterward, Dunn said he heard someone in the SUV shouting expletives and the word "cracker" at him. Dunn is white, and the teens in the SUV were black.

The music was turned back on, and Dunn testified, "I wasn't going to ask for favors anymore."

Dunn said the men in the SUV had "menacing expressions," and he asked the teens whether they were talking about him. He said he wanted to de-escalate the situation but saw a teen in the backseat reach down for something which he slammed into the car door. Dunn said it looked as if the barrel of a shotgun was sticking out the window.

One of the teens stepped out of the SUV, Dunn said, and he felt "this was a clear and present danger." He reached for his pistol in a glove box.

Dunn, who had a concealed weapons permit, fired nine shots into the car, according to an affidavit. Once his fiancee returned to the car, he drove off out of fear of the SUV returning, he said.

He described having "tunnel vision," with everything focused on his target.

No weapons were found in the SUV.

Dunn said he told his fiancee on the drive back to the hotel that he had shot in self-defense. The fiancee, Rouer, testified Saturday.

"I didn't do anything wrong," Dunn said he told his fiancee.

Dunn and Rouer drove back to their hotel without calling police. Dunn said he didn't call the police because his focus was on the well-being of Rouer, whom he described as in hysterics. The next morning, Dunn said, Rouer insisted they wanted to go home and they drove back to their home in Brevard County, 175 miles away. There, Dunn said he contacted a neighbor who is in law enforcement for advice on how to turn himself in to authorities.

During cross-examination, prosecutor John Guy challenged Dunn's assertion that he had told his fiancee after the shooting that he thought one of the teens had a gun.

"You never told the love of your life that those guys had a gun," Guy said. "Did you?"

Dunn responded, "You were not there."

Guy challenged Dunn on other parts of his story, citing letters Dunn had written from jail and interviews with investigators. The prosecutor said Dunn had told detectives the day after the shooting that it could have been a stick he saw pointing from the vehicle. But Dunn countered he was just suggesting a far-fetched possibility.

Guy also suggested that Dunn was angry because he was being disrespected by a young black man. Dunn responded, "I was being threatened, not disrespected."

The prosecutor also said Dunn had stated in a jailhouse letter that his car was parked so close to the SUV that it would have been hard for him to exit. Guy said that mean Davis also would have had a hard time getting out of the SUV.

"Jordan Davis was never a threat to you, was he, Mr. Dunn?" Guy said.

Dunn responded, "Absolutely, he was."