In the last two years, five other foreign men, including Mr. Dalglish, 60, have been arrested on suspicion of pedophilia, Mr. Karki said. “There have been some instances where they were found working with charities,” he said, noting that several of the men informally offered money, food and clothing to children. “Our laws aren’t as strict as in foreign countries, and there is no social scrutiny like in developed countries.”

The arrest of such a notable humanitarian has added urgency to a new effort by aid workers around the world, who are saying it is now time to investigate themselves. Late last year, they started a #MeToo-like movement called #AidToo.

In February, Oxfam, one of Britain’s largest charities, acknowledged that in 2011 four workers had been fired and three others had resigned after an investigation found that senior officials for the organization had hired prostitutes in Haiti, including for sex parties.

That same month, the BBC reported that men delivering aid on behalf of the United Nations and international charities had abused displaced women in Syria, trading food for sexual favors.

“Peter Dalglish’s arrest should be a ‘teachable moment’ for the humanitarian community to understand and recognize how predators exploit the cover of ‘heroism’ to commit crimes,” Lori Handrahan, a veteran humanitarian worker, wrote in an essay published on Medium. “Let’s be clear. Peter Dalglish is not a hero. He never was.”

Earlier this month, Mr. Dalglish was charged with pedophilia in a district court. He faces up to 13 years in prison.