Man convicted of killing sex partner, setting him on fire in 2011 faces new arson charges

Courtesy of SFPDDavid Munoz Diaz

Courtesy of SFPDDavid Munoz Diaz

A 25-year-old man convicted of involuntary manslaughter after allegedly killing a sexual partner and setting his body on fire in San Francisco's Buena Vista Park in 2011 appeared in court today after being arrested in the Castro District last week on suspicion of another act of arson.

The arson suspect, David Munoz Diaz, appeared in San Francisco Superior Court today wearing orange jail clothing, handcuffs, and a pair of thick black glasses. He took part in his arraignment today through the aid of a Spanish interpreter and did not enter a plea.

Diaz was arrested Wednesday for allegedly starting a fire early on the morning of Jan. 17 in front of a bar and hair salon located in the 4000 block of 18th Street, about a block from Castro Street, according to San Francisco police Officer Grace Gatpandan.

According to police, a storage room was reported to be on fire shortly before 5:30 a.m. on Jan. 17. Fire officials responded and determined that the fire might have been caused intentionally, prompting an arson investigation.

Officers arrested Diaz a couple of blocks away on Wednesday night and booked him into jail on suspicion of arson, Gatpandan said.

Diaz is charged with arson of an inhabited dwelling, arson of a vehicle, and for possession of an incendiary device, according to San Francisco District Attorney's Office spokesman Max Szabo.

San Francisco Superior Court Judge Ethan Schulman set Diaz's bail at $500,000 today.

A San Francisco jury last August found Diaz guilty of involuntary manslaughter but acquitted him of murder for the death of 23-year-old Freddy Roberto Canul-Arguello, whose body was set on fire in Buena Vista Park on June 10, 2011.

Szabo said the jury found Diaz guilty of mutilating human remains, misdemeanor destruction of evidence, and arson, but that the judge set aside the jury's arson verdict.

San Francisco Public Defender Jeff Adachi said Diaz was charged with fatally choking a sexual partner but had no previous criminal history and no motive to kill the victim.

The night Canul-Arguello died, the two men had run into each other while in the Castro neighborhood and decided to walk to Buena Vista Park to have sex.

Adachi said that during the sexual encounter, Canul-Arguello asked Diaz to choke him. Diaz reluctantly agreed but accidentally asphyxiated him.

According to the district attorney's office, Diaz panicked and then burned the body, leaving it in a blue recycling bin near the park's tennis courts just off of Buena Vista Avenue East near Haight Street.

Diaz was sentenced on Nov. 14 to four years in prison. He served more than three years while awaiting trial and, given his time in custody and credits accumulated, he was released on or shortly after his sentencing date.

According to San Francisco District Attorney's Office spokesman Alex Bastian, the judge in that case decided to set aside the arson charge because he felt it was unlikely that Diaz would commit arson following his release and that the charge was an undue burden on the defendant.

“The undue burden now rests squarely on the city and county of San Francisco,” Bastian said today.

Szabo said, “Undermining the jury's decision and setting aside the arson conviction hampers our ability to charge Diaz with enhancements relative to the new arson charges.”

Deputy Public Defender Alex Lilien is again representing Diaz after serving as his attorney in the previous trial. He said today that the charges are based on circumstantial evidence and maintained that Diaz “is a nice kid.”

San Francisco Assistant District Attorney Andrew Clark told the judge today that normally he would ask for a criminal protective order and a stayaway order, but said in this case, the victim was present in court and not interested in a criminal protective order against his partner.

Clark said there have been other recent fires in the Castro District that are being investigated as arson, but that no further charges have been filed against Diaz.

San Francisco police have not said what evidence led officers to arrest Diaz in connection with the Jan. 17 fire.

ArsonBay Area NewsBuena Vista ParkCrimeCrime & CourtsDavid Munoz Diaz

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