(CNN) -- In a quiet ceremony Friday at Arlington National Cemetery, a Marine killed three years ago in Iraq was reburied to be next to his close friend, a Navy SEAL who was recently killed in Afghanistan and who will be laid to rest alongside the Marine on Monday.
The two casualties, Lt. Travis Manion and Lt. Brendan Looney, met a decade ago while attending the United States Naval Academy. They became close friends and lived together from sophomore year until their graduation in 2004, Travis' sister, Ryan Manion-Borek, told CNN.
Their friendship was cut short in April 2007, when Manion was killed in Iraq during an ambush on the final patrol of his second tour of duty, according to the Department of Defense. He was 27.
According to the Defense Department's website, Manion's actions "ultimately saved the lives of every member of his patrol," and he was posthumously awarded the Silver Star and the Bronze Star with Valor.
The Iraqis named their new headquarters "Combat Outpost Manion."
Though Manion-Borek told CNN that her brother had "hoped to be buried in Arlington if anything happened to him," his family -- grief-stricken by the sudden loss -- chose to lay him to rest at a cemetery near his Pennsylvania home.
When Looney heard the news of his friend's death, he was in Navy SEAL training and unable to leave. The situation almost drove him to quit the program.
However, Manion-Borek said that after a phone call with Manion's mother Looney chose to stay, telling her he was, "finishing this for Travis." Looney went on to finish first in his SEAL class, a position known as "Honor Man."
Following Manion's death, his family founded the Travis Manion Foundation, which helps soldiers who are returning home after deployments and veterans. In the foundation's first appearance at the Marine Corps Marathon as "Team Travis," Looney was a teary-eyed guest speaker.
Even through training and deployment, Looney continued to stay close to the Manion family and the foundation.
But last week the Looney family got word that Brendan had died on September 21 in a black hawk helicopter crash in Afghanistan. He was 29.
"Brendan had told his brother that he would want to be buried next to Travis," Manion-Borek said.
When Looney's wife Amy first heard the news, "the first thing that came out of her mouth was, 'well then he has to be buried next to Travis,' " Manion-Borek said.
The Manion family immediately set to work with Arlington National Cemetery to try to transfer Travis' body.
His body was exhumed and transported to Arlington, where it was laid to rest Friday during a ceremony attended by both families. Looney's body will join him on Monday.
Describing the Looney family's presence at Friday's burial ceremony, Manion-Borek said that "every single one of them came up to me and said thank you."
"If anything can bring them comfort at this time, it's knowing that Brendan and Travis can be next to each other," she said.
Manion's sister said that the Looney family will be attending the Marine Corps Marathon this year, like usual. This year, however, "Team Travis" will be dedicated to Lt. Looney.