MEXICO CITY -- Mexico City authorities are investigating the death of a U.S. tourist killed by what appeared to be a stray bullet in a shooting at a taco restaurant in a wealthy capital neighborhood.The U.S. Bureau of Consular Affairs confirmed the death and released the victim's name, Tatiana Mirutenko, in a statement. She was reportedly from San Francisco.The city prosecutor's office says the 27-year-old American woman was leaving the restaurant early Saturday when gunmen aboard a motorcycle fired on a man authorities identified as a bouncer at an area bar.The man was wounded, but survived, and the attackers escaped.Authorities said in a statement later Saturday that Mirutenko was with her husband and two other friends at the restaurant in the Lomas de Chapultepec neighborhood.There was no indication the two victims knew each other.San Francisco's Nektar Therapeutics, where Mirutenko reportedly worked, released a statement that said, "Tatiana was a bright and passionate rising star. Many throughout Nektar, and outside the company, valued her positive energy, insight and sheer enthusiasm for life."