I learned that my 16-year-old grandson, Abdulrahman — a United States citizen — had been killed by an American drone strike from news reports the morning after he died.

The missile killed him, his teenage cousin and at least five other civilians on Oct. 14, 2011, while the boys were eating dinner at an open-air restaurant in southern Yemen.

I visited the site later, once I was able to bear the pain of seeing where he sat in his final moments. Local residents told me his body was blown to pieces. They showed me the grave where they buried his remains. I stood over it, asking why my grandchild was dead.

Nearly two years later, I still have no answers. The United States government has refused to explain why Abdulrahman was killed. It was not until May of this year that the Obama administration, in a supposed effort to be more transparent, publicly acknowledged what the world already knew — that it was responsible for his death.

The attorney general, Eric H. Holder Jr., said only that Abdulrahman was not “specifically targeted,” raising more questions than he answered.

My grandson was killed by his own government. The Obama administration must answer for its actions and be held accountable. On Friday, I will petition a federal court in Washington to require the government to do just that.

Abdulrahman was born in Denver. He lived in America until he was 7, then came to live with me in Yemen. He was a typical teenager — he watched “The Simpsons,” listened to Snoop Dogg, read “Harry Potter” and had a Facebook page with many friends. He had a mop of curly hair, glasses like me and a wide, goofy smile.

In 2010, the Obama administration put Abdulrahman’s father, my son Anwar, on C.I.A. and Pentagon “kill lists” of suspected terrorists targeted for death. A drone took his life on Sept. 30, 2011.

The government repeatedly made accusations of terrorism against Anwar — who was also an American citizen — but never charged him with a crime. No court ever reviewed the government’s claims nor was any evidence of criminal wrongdoing ever presented to a court. He did not deserve to be deprived of his constitutional rights as an American citizen and killed.

Early one morning in September 2011, Abdulrahman set out from our home in Sana by himself. He went to look for his father, whom he hadn’t seen for years. He left a note for his mother explaining that he missed his father and wanted to find him, and asking her to forgive him for leaving without permission.

A couple of days after Abdulrahman left, we were relieved to receive word that he was safe and with cousins in southern Yemen, where our family is from. Days later, his father was targeted and killed by American drones in a northern province, hundreds of miles away. After Anwar died, Abdulrahman called us and said he was going to return home.

That was the last time I heard his voice. He was killed just two weeks after his father.

A country that believes it does not even need to answer for killing its own is not the America I once knew. From 1966 to 1977, I fulfilled a childhood dream and studied in the United States as a Fulbright scholar, earning my doctorate and then working as a researcher and assistant professor at universities in New Mexico, Nebraska and Minnesota.

I have fond memories of those years. When I first came to the United States as a student, my host family took me camping by the ocean and on road trips to places like Yosemite, Disneyland and New York — and it was wonderful.

After returning to Yemen, I used my American education and skills to help my country, serving as Yemen’s minister of agriculture and fisheries and establishing one of the country’s leading institutions of higher learning, Ibb University. Abdulrahman used to tell me he wanted to follow in my footsteps and go back to America to study. I can’t bear to think of those conversations now.

After Anwar was put on the government’s list, but before he was killed, the American Civil Liberties Union and the Center for Constitutional Rights represented me in a lawsuit challenging the government’s claim that it could kill anyone it deemed an enemy of the state.

The court dismissed the case, saying that I did not have standing to sue on my son’s behalf and that the government’s targeted killing program was outside the court’s jurisdiction anyway.

After the deaths of Abdulrahman and Anwar, I filed another lawsuit, seeking answers and accountability. The government has argued once again that its targeted killing program is beyond the reach of the courts. I find it hard to believe that this can be legal in a constitutional democracy based on a system of checks and balances.

The government has killed a 16-year-old American boy. Shouldn’t it at least have to explain why?