A Tucsonan accused of fatally shooting a 74-year-old man in November 2010 did so in self-defense, his attorney told jurors Wednesday.

Witnesses will testify that Mario Hipolito Enriquez, 26, went to William Herr's south-side home to accompany a friend to whom Herr owed money from selling drugs and pirated DVDs, defense attorney Stan Bloom told jurors during opening statements of Enriquez's trial in Pima County Superior Court.

Herr was known to carry a gun, and Enriquez's friend asked him and two other people to meet him at the home for protection, Bloom said.

When Enriquez arrived at the home in the 7200 block of South Jill Place, Enriquez's friend was already inside the house and the door was ajar, so he walked in, Bloom said.

Enriquez went up to Herr, who fired at him, striking him twice, and Enriquez fired back, Bloom said.

Herr was shot twice in the leg and twice in the arm, called 911 and gave the dispatcher his name and address before becoming unresponsive, said prosecutor Jennifer Copenhaver-Celi.

Enriquez was arrested several months later after his ex-girlfriend told police he was involved in the shooting, Copenhaver-Celi said.

The woman said Enriquez showed up at her house after the shooting and said he was on his way to Mexico to be treated for his gunshot wounds, Copenhaver-Celi said.

The woman told police Herr was pushed to the floor and fired his gun upward and Enriquez shot him in response, the prosecutor said.

Enriquez is charged with first-degree murder and first-degree burglary.

Bloom said there is no evidence Enriquez intended to steal anything from the home and that nothing was taken.

Judge Jane Eikleberry is presiding over the trial.

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Contact reporter Veronica Cruz at vcruz@azstarnet.com or at 573-4224.