The man accused of killing a doctor and wounding five other people in a shooting at a Taiwanese-American church banquet in California methodically planned the attack because he was upset over Chinese-Taiwanese tensions, authorities said on Monday.
The suspect, David Chou, 68, chained the doors and placed glue in the locks at Geneva Presbyterian Church in Laguna Woods, California, about 45 miles (72 km) southeast of Los Angeles, before opening fire inside the church on Sunday, Orange County Sheriff Don Barnes said Monday.
Up to 40 people, members of a Taiwanese Presbyterian congregation from nearby Irvine, California, that has space in the church, were attending a luncheon honoring a former local pastor when the shooting began, sheriff's officials said.
Chou, described by the sheriff as a U.S. citizen and Las Vegas resident born in China, drove to Southern California on Saturday and came to the church on Sunday morning, authorities said. After the shooting, investigators found three bags placed around the church building with various items, including additional ammunition and four Molotov cocktail-like devices.
The FBI said it was opening a hate crimes investigation in the case.
The sheriff's department issued a statement late on Monday saying investigators had "determined that the suspect was upset about political tensions involving China and Taiwan" but did not elaborate.
In Chou's car, Barnes said, investigators found notes written in Mandarin that indicated an obsession with Taiwan and a dislike of Taiwanese people.
China views Taiwan, a democratically governed island, as its "sacred" territory and has never renounced the possible use of force to bring it under Beijing's control.
Taiwan rejects Beijing's sovereignty claims, saying that it is already independent and that only its 23 million people can decide their future.
All of the victims - whose names have not been released - were of Asian heritage.
The gun violence in California came on the same day as a separate mass shooting at a grocery store in a predominantly Black neighborhood of Buffalo, New York, that left 10 people dead and three others wounded. Most of the victims of that attack, which the FBI has labeled an act of racially motivated violent extremism, were Black.
Among those killed in the Laguna Woods church shooting was a physician Dr. John Cheng, 52, who was shot when he tackled the gunman, Barnes said, crediting Cheng's act of bravery with preventing more fatalities.
Subduing Chou gave other congregants, including a pastor, the opportunity to overpower him and tie his legs with an electrical cord, detaining him until sheriff's deputies arrived and broke through the chains on the doors.
Chou, who remains in custody, was believed to be acting alone, Barnes said. He purchased two guns used in the attack legally in Las Vegas, where he rented a room in a shared home. He likely will be charged with one count of murder, five counts of attempted murder and four counts of unlawful possession of explosives at an arraignment set for Tuesday, Orange County District Attorney Todd Spitzer told reporters.
The wounded, four men ranging in age from 66 to 92 and an 86-year-old woman, were taken to area hospitals for treatment, the sheriff's department said.
The shooting unfolded during a lunch reception the Taiwanese Presbyterian Church congregation had arranged for a former pastor who had left United States and relocated in Taiwan but returned for a visit, Tom Cramer, leader of the Presbytery of Los Ranchos and a former pastor at the Geneva Presbyterian Church, said in an interview.
Spitzer said he was considering seeking the death penalty in the case, though California has not executed a prisoner in more than a decade. Spitzer said he visited the church social hall on Sunday to see the carnage for himself.
Taiwan President Tsai Ing-wen was deeply concerned about the incident and has instructed the island's foreign ministry to help the victims and their families, the ministry said on Tuesday.