KABUL, Afghanistan -- Sgt. Nargis went to work Monday with murder on her mind.
By the end of the morning, she would succeed, becoming responsible for this year's 62nd insider killing, in which Afghan security forces have killed U.S. or other coalition personnel. Such killings have greatly increased this year, but Sgt. Nargis' killing of a U.S. police adviser, Joseph Griffin, 49, of Mansfield, Ga., ranks among the strangest.
Was she an Iranian agent, as Afghan officials suggested Tuesday after they found her Iranian passport at home? Was she mentally ill, as some police interrogators said privately and other Afghan officials speculated publicly?
The first theories, that she was either a jilted lover or a Taliban infiltrator, were rejected by the authorities Tuesday, but even her interrogators were left perplexed by her motives.
Making the case even stranger was her job: a uniformed police officer attached to the Interior Ministry's legal and gender equality unit, what would normally be seen as a plum job, one that is entirely underwritten by international aid, both American and European, earmarked specifically for women's rights issues.
All she would tell her interrogators was that she went to work aiming to kill someone important, and that she did not much care who, officials said.
"I was myself asking her, trying to make her talk about what could make her do such a thing, and all she would say was she wanted to kill a high official," said Gen. Mohammad Zaher, the director of the criminal investigation division of the Police Department in Kabul province, who attended her interrogations after her arrest Monday.
What she would not say, however, was why she had done it, he said.
"We just don't know," Gen. Zaher said.
Afghan security officials themselves have a well-founded fear of attacks by their own forces -- "green on green," or Afghan on Afghan, attacks have been even more common lately than attacks on foreign forces, with at least 14 Afghan police officers killed in such episodes in the past week. So even a uniformed police officer could not easily gain access to a building where she was not assigned.
As more detail about Sgt. Nargis emerged, it did little to shed any light on her motive.
Afghan officials at a news conference produced a copy of her Iranian passport, which showed she was 33 years old and, as with many Muslim women in conservative areas, had only one name of her own.
Intriguingly, Sgt. Nargis returned to Afghanistan less than a month ago from a monthlong police training program in Egypt. While on that course with other female officers, she disappeared for two days without ever giving a satisfactory explanation for her movements, according to a police official who spoke to other police officers who had been with her. The official spoke on the condition of anonymity because he was not authorized to release information about the case.
The only thing Afghan officials seemed to be certain of was that Sgt. Nargis was not a Taliban infiltrator. Even the Taliban did not claim as much, in a statement issued by the group quoting a spokesman, Zabiullah Mujahid, and reported by the monitoring organization SITE Intelligence Group on Monday. But Mr. Mujahid did add that such attacks had been on the increase not only by Taliban infiltrators but also by "Afghan soldiers who have an awakened conscience and feeling against the occupation forces."
That last theory resonated with one police commander close to the case. Either that, he said, or "she was just nuts."