Buena Vista Park murder trial arguments come to close

When two young men walked into a San Francisco park three years ago to have sex, either an adventurous strangling experiment went wrong or one of them went into a rage and strangled the other to death.

These two versions of a fatal 2011 night in Buena Vista Park were presented to jurors Monday in the closing arguments of the murder trial for David Munoz Diaz.

Diaz, a 25-year-old San Francisco resident from Mexico, has been charged with murdering Freddy Roberto Canul-Arguello and then mutilating his body by allegedly lighting a recycling bin on fire, which torched much of Canul-Arguello's body.

In the more-than-two-week trial before Superior Court Judge Donald Sullivan, jurors were shown DNA evidence and crime-scene photos and heard expert testimony on everything from strangling to arson.

But much of the case centered on sex, sexuality and sexual practices.

Lawyers deliberated about everything from a missing sex toy — dubbed the case of “where's the dildo” by one lawyer — to cross-dressing, erotic asphyxiation and even Mexican definitions of homosexuality.

The prosecution accused Diaz's lawyer of trying to malign gay men as being more promiscuous and drawn to risky sexual practices, such as erotic asphyxiation, which the defense said caused the accidental death of Canul-Arguello.

Defense lawyers called into question the prosecution's attempts to paint Diaz as a gay man who was nonetheless shaped by his upbringing with some ideals, which perceive a man who has gay sex as straight as long as he is the dominating partner.

Both the prosecution and the defense agreed on these simple facts: In the early-morning hours of June 10, 2011, the two young men met up at a Castro bar and then headed to Buena Vista Park, ostensibly to have sex. Once there, Canul-Arguello was strangled to death and then his body was burned by a plastic recycling bin set on fire by Diaz.

Whether Canul-Arguello died by accident while Diaz choked him during sex or was killed when Diaz went into a rage was debated. Equally debated was whether the recycling bin set afire by Diaz was a signal fire for help or a deliberate effort to destroy evidence.

“This was no accident,” prosecutor Danielle Douglas said. “Freddy's life was taken.”

Diaz, argued Douglas, strangled his victim, fracturing cartilage in the man's throat, and then tried to cover up his crime by burning the evidence and lying repeatedly to police.

But Alex Lilien, Diaz's public defender, argued that two men inexperienced with kink experimented and things went tragically wrong.

Jurors are scheduled to begin deliberating with a verdict expected as early as today.

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