At the time, Smith served as the United States' ambassador to the country. But it was his potential new post that prompted U.S. Sen. Patrick Toomey to ask Smith for a full account of his actions.
The Pennsylvania Republican posed his questions as part of the run-up to Smith's expected Senate confirmation vote later this year.
"I remain deeply saddened by the tragic death of Sgt. LaLoup, and the subsequent events regarding his heart," Smith wrote in response to Toomey. "From the outset, this matter was a high priority for me. I personally raised the issue at the most senior levels of the Greek government, pressing for a full investigation and accounting as well as the return of Sgt. LaLoup's heart."
Smith's response was outlined in an e-mail sent to LaLoup's family from Toomey's office and later obtained by The Inquirer. It offers the most detailed picture yet of the U.S. response to questions surrounding the handling of the Marine's remains.
Attempts to reach Smith directly were unsuccessful Monday. State Department officials have repeatedly said their investigation continues.
Last month, LaLoup's family sued the U.S. and Greek governments, claiming a government-run hospital in Athens removed their son's heart in an illegal autopsy. The story they spun in court filings is as bizarre as it is troubling.
LaLoup, who was stationed as an embassy security officer in Athens, fatally shot himself Aug. 12, 2012, after a night of heavy drinking.
But his family claimed U.S. military officials never informed them that their son's remains were incomplete until well after his burial - and even then only when an officer let the fact slip in conversation.
The hospital and the Defense Department later claimed to have located LaLoup's missing heart and sent it back to the United States. But testing later revealed that heart did not match the Marine's DNA.
More than a year later, the LaLoups say they are no closer to finding out what happened to their son's heart or where the heart they were sent came from.
In his response to Toomey's questioning last week, Smith firmly sided with the LaLoups' claims that their son's autopsy in Greece was improper.
Three times before the procedure occurred, he attempted to block it, appealing as high as chief officers in the Greek Ministry of Foreign Affairs, he said.
Typically, the remains of service members killed overseas are sent back to the United States for postmortem investigations.
In response to Toomey's questions last week, Smith said he personally demanded an "immediate and thorough" investigation when he learned that LaLoup's heart had disappeared and continued to follow up on that demand until his last day as ambassador in August.
But his calls for answers appeared to go unanswered.
"As a father of three sons, including one serving in the U.S. Army, I have the greatest sympathy for Mr. and Mrs. LaLoup and what they have gone through," Smith said in his response to Toomey.
Christos Failadis, a spokesman to the Greek Embassy in Washington, has previously said LaLoup's heart was removed for toxicology testing, but he offered no insight into where the heart might be now or Greek efforts to recover it. He did not return calls for comment Monday.
Aaron J. Freiwald, an attorney representing the LaLoups in their suit against the United States and Greece, said that while his clients were thankful for Smith's responses, they raised even more questions.
"This was really the first significant confirmation that the State Department believes that what happened was unlawful," he said. "But it seems hard to believe that if the U.S. ambassador says he wants to know something, he would get no answer."
Smith's nomination to his new post was approved by the Senate intelligence committee last week. He awaits a confirmation vote from the full Senate later this year.