SAN DIEGO, California (CNN) -- A Korean immigrant who lost his wife, two children and mother-in-law when a Marine Corps jet slammed into the family's house said Tuesday he did not blame the pilot, who ejected and survived.

Dong Yun Yoon said his 15-month-old daughter, Grace, was killed after a military jet crashed into his home. more photos »

"Please pray for him not to suffer from this accident," a distraught Dong Yun Yoon told reporters gathered near the site of Monday's crash of an F/A-18D jet in San Diego's University City community.

"He is one of our treasures for the country," Yoon said in accented English punctuated by long pauses while he tried to maintain his composure.

"I don't blame him. I don't have any hard feelings. I know he did everything he could," said Yoon, flanked by members of San Diego's Korean community, relatives and members from the family's church. Watch Yoon discuss relatives' death »

Authorities said four people died when the jet crashed into the Yoon family's house while the pilot was trying to reach nearby Marine Corps Air Station Miramar. Another unoccupied house also was destroyed.

Yoon named the victims as his infant daughter Rachel, who was born less than two months ago; his 15-month-old daughter Grace; his wife, Young Mi Yoon, 36; and her 60-year-old mother, Suk Im Kim, who he said had come to the United States from Korea recently to help take care of the children.

Fighting back tears, he said of his daughters: "I cannot believe that they are not here right now."

"I know there are many people who have experienced more terrible things," Yoon said. "But, please, tell me how to do it. I don't know what to do."

Marine Corps authorities said the pilot, whose name was not released, was hospitalized after he parachuted from the jet, and an investigation into the cause of the crash has been launched. iReport.com: Eyewitnesses describe chaos in aftermath

The jet had just performed landing training on a Navy aircraft carrier before the pilot reported having trouble, according to the Marine Corps. Authorities described the jet as disabled.

Three bodies -- those of two adults and an infant -- were recovered hours after the crash on Monday. The fourth body -- that of a child -- was recovered Tuesday, as firefighters sifted through the rubble of the Yoon house.

Authorities said they did not expect to find any other victims of the crash.

The area's congressman, Rep. Duncan Hunter, said after a briefing from the Marine Corps that a power failure was the likely cause of the crash, not any structural problem with the aircraft.

"At this time, my deepest sympathies are with all those who have been affected by this incident, especially those who lost loved ones," Hunter, the ranking Republican on the House Armed Services Committee, said in a statement from his office.

Yoon's minister, Daniel Shin, told reporters the Yoon family had moved into the house a little more than a month ago. He said Yoon came to the United States in 1989 and had since become a naturalized citizen. Yoon works as manager of "a variety store -- a store where they sell a variety of things," Shin said.

Yoon's wife came to the United States about four years ago, Shin said.

Yoon spoke softly when he talked about his wife.

"It was God's blessing that I met her about four years ago. She was a lovely wife and mother," he said.

His voice fading, he added: "She loves me and babies. I just miss her so much."

The Marine Corps said Tuesday it would take "a minimum of five to seven working days" to clean up the crash site.

San Diego resident Ian Lerner said he was heading to lunch at a shopping center about a half-mile from the neighborhood of about 20 homes when he saw the jet flying low.

"It was, oh, gosh, maybe a couple of hundred feet off the ground. And it was quiet; I think the engine was off," Lerner said. iReport.com: See Lerner's photos

"Then all of a sudden, we saw the canopy of the jet explode and go up, and then we saw the pilot blast out of the plane and the parachute open," Lerner said. Watch a witness describe the pilot's main concern »

Another witness said the jet was flying at a low altitude and "just spiraled, right out of [the movie] 'Top Gun.' "

A photograph taken at the crash site showed the pilot, after ejection, sitting on the front lawn, making a call on his cell phone before he was taken to a hospital. Watch burning debris near crash site »

The pilot was the only occupant of the two-seat aircraft, according to the Marine Corps.

The Union-Tribune spoke with Steve Diamond, a retired naval aviator who said he found the pilot in a tree behind a house. He told the paper he helped the man, who Diamond said was a lieutenant in his 20s, down from the tree. See satellite photo showing crash site, airfield »

The pilot told him that after he lost power in one engine, it was decided he would try to get the jet to Miramar on the single working engine, Diamond told the paper.

The pilot was in communication with military air traffic controllers before the jet crashed about two miles from the airfield, the Federal Aviation Administration said.

According to the Los Angeles Times, the pilot ejected moments before the crash and landed in a tree. Jason Widmer said he talked to the pilot, who said he had tried to steer the jet from the homes and into a brushy canyon.

"He was pretty shook up and pretty concerned if he had killed anyone," Widmer told San Diego 6. "He had seen his bird go into a house."

A retired general, a pilot who has flown for 40 years and more than 270 missions in Vietnam, said the decision to eject is up to the pilot. F/A-18D planes are very dependable, but any aircraft is subject to error.

That model has two engines, and it can operate with one engine. But if one engine malfunctions, it's possible that a blade can break off and fly into the other engine, causing it to malfunction, too. If both engines are inoperable and the plane descends below 10,000 feet, it's likely the pilot will soon lose control.

To eject, a pilot pulls a ring-like lever. The jet's canopy is propelled off the aircraft, quickly followed by the pilot in an ejection seat. A pilot can opt to manually activate his parachute, but if he doesn't, the parachute will open on a timer.

The plane would crash randomly once the pilot is no longer in control. See photos of fiery crash site »

Inside a house in the neighborhood, Robert Johnson sat in his living room with his daughter, Heather Certain, and her 2-year-old son, Nicholas, according to the Union-Tribune. They heard the explosion and then saw a giant fireball in the picture window facing their front yard, the newspaper reported. They ran out of the house. Watch aerial footage of crash site »

"The house shook like an earthquake," Johnson said. "I saw the flames right there in front of my house."

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