WASHINGTON » Standing on the marble floor just outside the House chamber, Faisal bin Ali Jaber looked lost in the human river of hard-charging lobbyists, members of Congress and staffers. It is not every day that a victim of U.S. drone strikes travels 7,000 miles to Washington to look for answers.

Now he stood face to face with Rep. Adam B. Schiff, D-Calif. — who had carved out 20 minutes between two votes on natural gas policy — to tell his story: how he watched in horror last year as drone-fired missiles incinerated his nephew and brother-in-law in a remote Yemeni village.

Neither of the victims was a member of al-Qaida. In fact, the opposite was true. They were meeting with three al-Qaida members in hopes of changing the militants’ views.

"It really puts a human face on the term ‘collateral damage,’" said Schiff, looking awed after listening to Jaber.

A gaunt civil engineer with a white mustache, Jaber spent the past week struggling to pierce the veil of secrecy and anonymity over the Obama administration’s drone strike program, which targets militants in the hinterlands of Afghanistan, Pakistan and Yemen. He did not have much luck.

He met at length with a half-dozen members of Congress, as well as officials from the National Security Council and the State Department. Everywhere, he received heartfelt condolences. But no one has been able to explain why his relatives were killed, or why the administration is not willing to acknowledge its mistake.

It was an error with unusual resonance. Jaber’s brother-in-law was a cleric who had spoken out against al-Qaida shortly before the drone killed him. The nephew was a local policeman who had come along in part to offer protection. The strike, in August 2012, drew widespread indignation in Yemen, and was documented in The and later by human rights groups, along with a number of other strikes that accidentally killed innocent people.

A Yemeni counterterrorism official called Jaber hours after the strike to apologize for the mistake. Jaber wrote an open letter to President Barack Obama, but received no answer. The same is true of a Pakistani family who lost a grandmother in a drone strike and visited Washington briefly late last month, in what appears to be the first such visit to Congress.

In May, Obama responded to rising criticism of the targeted killing program and acknowledged in a speech at the National Defense University in Washington that some innocent people had been killed. The president promised greater transparency, but the administration still refuses to discuss specific strikes or to apologize or pay compensation for strikes that went wrong. When U.S. officials have offered estimates of civilian casualties in drone strikes, their numbers have been far lower than those given by research groups and journalists.

Jaber’s visit — and that of the Pakistani family — comes as a congressional effort is building to force the administration’s hand. Early this month, the Senate Intelligence Committee added to the annual intelligence policy bill a requirement for an annual report giving the number of "combatants" and "noncombatant civilians" killed or injured in the previous year in drone strikes outside conventional wars. The report would give only total numbers, not details of each strike or the names of those killed.

Schiff, who met Jaber on Wednesday, plans to sponsor a similar bill in the House.

Jaber’s visit was sponsored by the peace group Code Pink, which organized an accompanying protest in front of the White House last week, and Reprieve, a human rights group based in London.

Unlike some of the activists who embraced him and apologized to him wherever he went, Jaber strikes a very humble and unassuming attitude about his family’s tragedy. He says he does not presume to pass judgment on the drone strike program itself, but wants acknowledgment and an apology.

"I learned two things," he said when asked to sum up his week in Washington. "First, the American people and their organizations are very kind and well meaning, and the Congress members also were very sympathetic. But on the other side, there are politicians who seem to be trying to keep everything secret."

Jaber offers a harrowing account of the drone strike. It was the day after his son’s wedding in his native village, Khashamir, and he was eating dinner at home with several relatives when they heard a whirring from the sky. Looking out the window, he and his relatives saw a flash, and then heard a series of terrific crashes, "as if the whole mountain had exploded." The village erupted in panic.

Jaber’s daughter, who was very close to the strike, was so traumatized that she did not get out of bed for three weeks, he said. The mother of one of the dead men went into a coma and died a month later.

When Jaber arrived on the scene that night, less than a mile from his house, he found bits of charred human flesh spread on the ground, he said. It was not until two hours later, through the accounts of witnesses, that the identities of the dead men and what had happened to them became clear.

Jaber’s brother-in-law, the imam, had been approached earlier that evening by three al-Qaida militants who were angry about a speech the imam had delivered condemning terrorism. The imam reluctantly agreed to talk to the men, but just in case he was accompanied by Jaber’s nephew, the policeman. The volley of missiles killed all five men.

Like most Yemenis, Jaber deplores the influence of al-Qaida in his country, which is one of the world’s poorest. He fears that the drone strikes are fostering greater militancy and anger at America. But above all, he finds the administration’s silence baffling.

At one point during his week in Washington, Jaber got a tour of the National Mall and other landmarks with another Yemeni who had been flown over for the visit, a young woman named Entesar al Qadhi. Both of them said they were overwhelmed by the dignity and calm of the Mall, so different from the crowds and poverty of Yemen.

"They have such a beautiful country here, such a beautiful city," Qadhi said as she strolled along. "Why do they need to go chasing someone with bombs in the desert?"