His wife, two children and mother-in-law were killed when a fighter jet lost power and crashed through their home and burst into flames. A day after the tragedy, Yoon held a news conference to ask guidance from people who have suffered "more terrible things."
"Please tell me how to do it," he said Tuesday, surrounded by his pastor, sister and brother. "I don't know what to do."
Yoon, sobbing into a tissue at the foot of his destroyed house, also asked for prayer for the jet's Marine pilot, who ejected safely from the F/A-18D Hornet after his training mission went awry Monday.
"I don't have any hard feelings," Yoon, 37, told reporters. "I know he did everything he could."
The military has given no official word on the cause of the crash, which incinerated two homes and damaged three others.
He said the fiery crash was apparently caused by power failure. "My understanding ... is that the engines failed, causing the aircraft to lose thrust," Hunter spokesman Joe Kasper said.
The crash was probably unrelated to the previous discovery of cracks in hinges on the wings of more than a dozen of the $57 million aircraft, the San Diego-area congressman said.
"It is important that we gain a complete understanding of what went wrong," Hunter said.
The jet was returning from an offshore training mission when it clipped a tree and slammed into the neighborhood about two miles from Marine Corps Air Station Miramar.
The Rev. Kevin Lee, associate pastor of the Korean United Methodist Church that Yoon attended, identified the victims as Young Mi Yoon, 36; her daughters Grace, 15 months, and Rachel, 2 months; and her mother, Suk Im Kim, 60. Lee said Kim was visiting from South Korea to help her daughter move across town and adjust to the arrival of her second child.
Dong Yun Yoon emigrated from South Korea in 1989, learning English and becoming a U.S. citizen, church leaders said. He helped run his brother-in-law's stores - a coffee shop in a San Diego beach neighborhood and a variety store near the Mexican border, according to Michael Rose, a neighbor.
The family had recently moved into the area after outgrowing their condominium.
Neighbors and church leaders said Young Mi Yoon was a religious woman who sought to balance family and career. She was preparing to become a registered nurse, her job in South Korea.
Rose, 44, saw Dong Yun Yoon say goodbye to his wife and baby in their driveway as he left for work Monday, about three hours before the fighter jet clipped a jacaranda tree, bounced off the pavement and crashed into the Yoons' home.
"I saw their last kiss," said Rose, a retired photographer. "I thought, `What a beautiful sight,' and then later in the day they were just gone."