(Update: Edhi returned to Karachi on Feb. 4.)

When U.S. immigration officers question an arriving Pakistani for eight hours and seize his passport, they presumably suspect some kind of link to Islamist terrorism. Abdul Sattar Edhi, 79, “has links” to some horrifying violence, so to speak, but it’s hard to imagine they’re the kind that immigration officers may have suspected when they detained him at New York’s Kennedy Airport on Jan. 9.

Edhi and his colleagues care for — and, when necessary, bury — the victims of violence in his native city Karachi. His private Edhi Welfare Trust foundation runs an extensive ambulance service, buries unclaimed bodies and maintains centres for orphans, the homeless, the addicted and the mentally ill. In a country where state-run welfare services are basic or non-existant, his charity work is so unusual and prominent that he is often called “Pakistan’s Mother Teresa”.

When a bomb blast in Karachi last October killed 139 supporters of opposition leader Benazir Bhutto (herself later assassinated), Edhi ambulances were among the first helpers to arrive at the scene. One report noted the trust collected 110 of the victims, and washed and wrapped them in shrouds according to Muslim custom at its morgue so relatives could claim them.

When Wall Street Journal reporter Daniel Pearl’s body was found in Karachi months after he was murdered, it went first to the Edhi Trust morgue before being shipped home to the United States.

In late 2001, as U.S.-backed Afghan forces fought to overthrow the Taliban, the Edhi Trust sent ambulances from Pakistani border areas into Taliban strongholds in southern Afghanistan to bring out civilian casualties for treatment. The Trust also rushed workers and aid to northern Pakistan when a serious earthquake hit it in 2005. It has offices in several other countries, including the United States, and also rushed aid to the victims of Hurricane Katrina.

Pakistan’s government and media are up in arms over the detention, which means Edhi, 78, is now stuck in New York until at least February 20.

“During the interrogation, they wanted to know why I travelled to the U.S. so frequently,” Edhi told the BBC on Tuesday from New York. “I told them about the nature of my work, but they did not understand. They also wanted to know why I was not living in the U.S. in spite of having a green card. I am a man of emergencies, I need to be on the move, to be where the suffering is, but here I have been sitting idle for 20 days because I cannot travel without my passport.”

When I was a correspondent in Pakistan in the mid-1980s, I once visited Edhi in his sparse Karachi office and asked him how he started making morning rounds in the rough-and-tumble city to pick up unclaimed dead bodies. “I thought they deserved a decent Muslim burial,” he told me simply.