When Hank Londner approached Capt. Humayun Khan's gravestone in Arlington National Cemetery on Wednesday afternoon he had a card in his hands and tears in his eyes.

The tears were for the 27-year-old soldier who was killed by a suicide bomber in Iraq in 2004, and the card was for his parents, whose criticism of Republican presidential nominee Donald Trump has thrust them into the middle of the 2016 election campaign.

"Dear Mr. and Mrs. Khan, I have been so moved by your courage and action and words that I was compelled to come here to pay my respects for the ultimate sacrifice of Humayun and your family," Londner wrote.

The 65-year-old told Khizr and Ghazala Khan that he is Jewish, gay and the son of Holocaust survivors who brought him to the United States when he was 10. "I feel I understand the meaning of the sacrifice made by all those around me at this hallowed ground. I can only thank you for all you have done and given, and wish you peace."

He placed the card among the bouquets of flowers that surround Khan's gravestone, a collection that grew larger through the week. Londner was one of several people who visited the grave of someone they never knew and who were overcome by emotion when they got there.

Amir Vangieson, 15, visited Capt. Humayun Khan's grave on Wednesday and brought a sketch pad to make an etching of it. He was there with his father, who served in the U.S. Army. (Meagan Fitzpatrick/CBC) Mark Greco, a 59-year-old navy veteran, choked up when asked what brought him to Arlington. He took a moment to compose himself.

"I feel that his family has been maligned by you know who. I feel he deserves the respect that he is not being shown by Trump," said Greco, whose grandfather is buried in the historic cemetery. He views Trump's treatment of the Khans as "a betrayal" of all veterans.

A dedicated soldier

Khan's parents came to the U.S. from Pakistan when he was two. They raised their three sons in the suburbs of Washington, D.C. When the boys were young their father, a lawyer who carries a pocket-sized American Constitution with him, would often take them to the Thomas Jefferson Memorial.

He told the Washington Post his middle son Humayun admired the Founding Father who authored the Declaration of Independence and that he quoted Jefferson in his application essay for the University of Virginia, which Jefferson founded.

It was there that Humayun Khan signed up for the Reserve Officers' Training Corps. His parents weren't happy about it, but Khan wanted to give back. His dedication propelled him up the ranks to captain.

He was set on a course that led him to Iraq after he graduated with a psychology degree and his plans to go to law school were put on hold.

On June 8, 2004, a speeding taxi approached Khan's base. He saw it and yelled for his soldiers to get out of harm's way. He ran toward it, motioning for the driver to stop. The car full of explosives detonated and he was killed.

Khan was praised for preventing the deaths of the soldiers under his command and lauded as an excellent leader who was devoted to the idea of safeguarding freedom and his soldiers.

Capt. Humayun Khan's grave is marked with a crescent moon to symbolize his Muslim faith. (Meagan Fitzpatrick/CBC)

Khan never would have lived in the U.S. or died fighting for its protection if Trump had his way, his father said on stage at the Democratic Party convention last week

Khizr Khan denounced Trump's proposed ban on Muslims, pulled his worn copy of the constitution from his jacket pocket and asked if Trump had ever read it. Then he asked if Trump had ever visited the historic cemetery where his son is buried. "You have sacrificed nothing, and no one," he said.

Arlington cemetery is the final resting place for more than 400,000 service members and their families. Rows upon rows of white marble headstones stretch across the acres of green rolling hills.

Khizr Khan, father of fallen U.S. Army Capt. Humayun Khan, holds up a copy of the U.S. Constitution as his wife Ghazala listens on July 28 during the Democratic National Convention in Philadelphia. 'You have sacrificed nothing,' he told Republican presidential nominee Donald Trump. (Associated Press) Khan's grave is in Section 60, surrounded by the graves of hundreds of young men and women who lost their lives in Iraq and Afghanistan.

Trump responded to the Khans in an interview, saying he's made lots of sacrifices and works hard. He also suggested that Mrs. Khan may have stayed silent during her husband's remarks because her religion prohibited her from speaking.

The next day she wrote an op-ed in the Washington Post explaining that she is too emotional to speak about her son on a stage in front of millions of people.

The feud escalated when the couple gave interviews where they criticized Trump, and he maintained they "viciously attacked" him. He has not given in to the pressure to apologize and show more empathy towards them, and he says he has "no regrets" about how he's handled it.

But it's become a big distraction and a flashpoint in the campaign, prompting a long list of people in Trump's own party to publicly reject his conduct. But as the scene at the cemetery showed on Wednesday, it's also triggered emotional responses of support for the Khans.

"I came here specifically to honour Capt. Khan and his family," Ron Matwey said after planting two miniature American flags on either side of the headstone. "I feel like his family represents the best of America."

Ron Matwey wants to honour Capt. Khan, who died during the Iraq War and whose parents have been criticized by Donald Trump 0:46

Ajija Vangieson arrived a few minutes later with her husband Pono, who served in the army for 25 years, and their teenage son and daughter. She wants the Khans to know how grateful she is for their son's sacrifice.

"He sacrificed his life defending our country and the right for Mr. Trump to say whatever bullshit he wants to say … even insulting his parents and any other Gold Star family," she said.

Strangers shed tears for Khan

Vangieson is a Muslim, has a physical disability, immigrated from India when she was five and is a military spouse, making her a member of multiple groups she feels Trump has offended.

She said she is no fan of Democratic nominee Hillary Clinton either, but Trump has "no soul," and no ability to empathize.

Looking around the cemetery at the thousands of graves, Vangieson said Trump's campaign slogan, "Make America Great Again," is ironic. "He doesn't get how great of a country this is and how many have sacrificed their lives to keep this country as great as it is," she said.

Thomas Hernandez was feeling similarly patriotic while he stood before Khan's headstone, bicycle helmet tucked under his arm. He lifted his sunglasses to wipe away the tears that had unexpectedly seeped out.

Amber Friesen, left, and her sister Allison Esau, Canadians visiting Washington, D.C., went to Arlington cemetery to pay their respects to Capt. Humayun Khan. (Meagan Fitzpatrick/CBC)

"It was more emotional than I thought it would be," said the young man, who is the same age Khan was when he died. When he heard about the Khans in the news, Hernandez said, it reminded him of America's ideals, including freedom and bravery, and how Khan perfectly represented them.

"I just wanted to honour that," he said.

It wasn't just patriotic Americans who were drawn to Arlington to pay their respects. A pair of Canadians were there, too.

Amber Friesen, who lives in San Francisco and was in Washington for a conference, said coming to the cemetery was a way to show support for the family and to stand up to some of the hateful things she thinks Trump has said.

Her sister, Allison Esau, in town from Vancouver, said it's touching that Americans are supporting the family. "It's a special thing to see," said Esau.