David Wenwei Chou, 68, of Las Vegas, is charged with carrying out the mass shooting at a lunch gathering of elderly parishioners at Irvine Taiwanese Presbyterian Church in Laguna Woods, killing a 52-year-old doctor and wounding five others.
Prosecutors filed an amended complaint this week to add a special circumstance that Chou intentionally killed his victim because of his race, color, religion, nationality, or country of origin, and five enhancements of a hate crime for each of the five counts of attempted murder, the Orange County district attorney's office said in a Friday statement.
Chou is also facing four felony counts of possession of an explosive device, and felony enhancements of lying in wait and personal discharge of a firearm causing death.
Authorities have said Chou sat through a church service before attending the luncheon in honor of a former pastor, where he mingled with the parishioners for about 40 minutes before chaining and nailing shut exit doors and opening fire.
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When the gunfire erupted, Dr. John Cheng, 52, charged Chou and was shot but authorities said he disrupted the attack and may have saved dozens of lives.
The former pastor, Billy Chang, then picked up a chair and threw it at Chou, who fell on the floor. Chang said he rushed at Chou and several congregation members held Chou down and tied him up.
Chou was armed with two legally purchased 9 mm handguns and concealed bags holding ammunition and four Molotov cocktail-style devices in the church hall where the luncheon was being held, authorities said.
The Associated Press contributed to this report.