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More than half a century ago, Deborah Crosby was sent home from the first grade to find military officers in her living room and her mother distraught: Her father's Navy plane had been shot down in northern Vietnam, and he was presumed dead, though his body had not been found.

Her mother could never talk about that day, but she gave Crosby and her three brothers a binder with articles about her father's plane zooming low through the clouds on a bomb damage assessment mission before it was gunned down by North Vietnamese ground forces in 1965. The 31-year-old pilot was armed only with cameras, his daughter said.

Crosby and her grandmother made a pact to someday bring home the remains of Lt. Commander Frederick P. Crosby and bury him in his hometown of San Diego.

A year ago, military investigators found his remains and on Friday, Crosby will fulfill that promise to her late grandmother by receiving her father's casket at the airport in San Diego. On Sunday, Frederick Crosby will be buried at Rosecrans National Cemetery with full military honors and a Navy flyover.

Crosby never doubted the fact that her father was killed. But her grief seemed to linger in a deep space inside her until she received news that his remains had been recovered, finally giving her closure.

"It just changed my life in so many ways," said the energy consultant who lives in New York. "It relieved a lot of sadness that I've been carrying around in my heart very quietly."

The U.S. military actively searches for missing service members from conflicts worldwide. According to the National League of Families of American Prisoners and Missing in Southeast Asia, 969 missing service members have been accounted for since the end of the Vietnam War in 1975, while the whereabouts of 1,611 remain a mystery.

Crosby called to inquire regularly about the military's progress on her father's case. She attended meetings of the National League, and analyzed where the crash occurred in Thanh Hoa province on Google Earth. She poured over news reels and reports at the Library of Congress and provided a sample of her aunt's blood to the military to have a DNA match on file in case his remains were ever found.

Decades passed and her mother and grandmother both died before investigators got a breakthrough on their third trip to the area when they met Pham Van Truong, a lifelong resident of Nam Ngan ward in Thanh Hoa City.

According to a 50-page report given to Crosby, the 89-year-old man told investigators he couldn't recall the month or year but he remembered during the war that he was cooking limestone to reinforce his house when he heard gunfire and ran to the nearby levee to investigate. He saw two planes headed toward his house and one was on fire as it glided toward the levee. He said he could see its wing and tail surfaces were missing. The aircraft rolled as it hit the fish pond in front of his house, splashing Van Truong with water and mud. The other aircraft kept flying toward the sea.

Van Truong told investigators that shortly after it crashed, a Vietnamese salvage team had pulled some parts of the plane, including the engine, from the pond and hauled it away. Van Truong, who had helped the salvage team, kept a piece of the plane to use for making a cooking utensil. He also used a piece of its glass to repair a clock.

Based on the new information, U.S. military investigators decided to comb the bottom of the pond in 2015. When they emptied it bucket by bucket, they found bones, pieces of fabric from Crosby's uniform, his chrome lighter and wedding band.

Crosby still keeps the voicemail on her phone from a year ago when a military official left a message telling her to call for news about her dad.

"When I called, he introduced himself and said, `We have your dad's remains and they've been positively identified,"' Crosby, 58, said. "I burst into tears. I basically told him it's almost like that same day I remember when I was 6 years old. It was almost like getting the knock on the door by the military."

She felt she could finally shed the tears stored up inside of her.

Crosby said her brothers want to keep the fabric, lighter and wedding band.

She just wants the flag draped over his coffin.

"I think my mom would be very happy that my dad is getting the military honors and the recognition of the hero that he was," she said. "There is so much relief in my heart. I'm so overjoyed that my grandmother's wishes came true and dad is coming home."