In the months before he was captured in a Taliban prison uprising in Afghanistan, John Walker Lindh's mother sent increasingly anguished letters to a Pakistani religious school pleading for information about his whereabouts.

"I have not heard from Sulayman and I am saddened," Marilyn Walker said in the last of four letters, referring to her son by the Muslim name he had adopted after leaving the United States. "Please write to me if you have news from him. Please find the time to write a letter to me."

The letter, written in the Pakistani language Urdu — apparently with the help of a translator in the United States — was postmarked Oct. 9, just weeks before Walker was captured in a bloody uprising by Taliban and Al Qaeda prisoners near the northern Afghan city of Mazar-e-Sharif. An American CIA operative, Johnny "Mike" Spann, was killed during the uprising.

Walker was arraigned Thursday in U.S. District Court in Alexandria, Va., on a charge of conspiring to kill his fellow Americans in Afghanistan. The 20-year-old Californian faces life imprisonment if convicted.

At the hearing, Walker never turned to look at his parents, who were sitting two rows behind him. Afterward, his mother said her love for her son was "unconditional and absolute."

"I am grateful to God that he has been brought home to his family, me, his home and his country," she said, fighting back tears.

At the school in Pakistan, the stack of letters, all from his mother, and Walker's other personal effects — a suitcase full of clothes and a shelf of Islamic books — have been carefully preserved. Walker left the school in May, telling his family he was moving "into the mountains" for the summer. He did not receive any of his mother's correspondence.

In one of the first letters sent to the school, Marilyn Walker pleaded with her son to contact her.

"I am not going to write much here because I am not certain it will reach you," she wrote in a letter postmarked June 30. "I really need to hear your voice, John. So, please call collect and tell me what's up. Miss you. Love you."

Later, she appealed to the school's headmaster, Mufti Mohammed Iltimas, for information about her son. Iltimas shared her letters with The Associated Press, and translated the one written in Urdu, postmarked Oct. 9.

"I have lost touch with my son, Sulayman Lindh al-Faris," she wrote in a letter dated July 10. "The last I heard from him (via e-mail) was April 26th. He said he might be moving into the mountains for a cooler climate during the summer months. Would you know where he is now and how I may reach him or could you get a message to him to call 'collect' or write? I appreciate very much any help and attention you may give and thank you."

In his reply, Iltimas wrote Walker's mother to reassure her that her son was well, but made no mention of his whereabouts.

"Rest assured that he is my student and also my younger brother," Iltimas wrote. "He is very sweet, honest, God-fearing and a very decent human being. All of us who know him give you credit for being the mother of a person like Sulayman al-Faris. May Allah give him a happy and a prosperous long life."

Marilyn Walker replied on August 19, saying "I cannot tell you how much it means to me to know that he is cared for in a land so far from his home. We miss him very much. It isn't like him to have gone so long without making contact with us."

Walker, a convert to Islam, was traveling in Pakistan following a stint in Yemen when he met Iltimas in the market of this village and asked to be admitted as a student to the school, called the Madrassa-e-Arabia, or Arabic School.

He was accepted and spent six months there, starting in November 2000, despite being older than any of the school's other students. Faculty and classmates remember him as a quiet young man who spent his time reading Islamic books and memorizing the Muslim holy book, the Quran.

"He was a good and pure person," said Zial ul-Rahman, 13, who took Quranic lessons with Lindh in the school's mosque, a Spartan structure with cheap blue carpets, ceiling fans and whitewashed walls.

Seated in a carpeted room where Walker studied and sometimes slept, Iltimas said the young American spoke fluent classical Arabic, was well versed on Islamic law and enjoyed reading.

"He adhered to Ibn Hanbal's creed," said Iltimas, referring to the medieval founder of the most rigorous school of Islamic law, preferred by militant Muslim groups the world over. "He would occasionally come with me when I was invited to functions, but only if that didn't clash with his lessons or his studies."

Walker had learned Arabic in Yemen, where he spent 17 months following his conversion to Islam. He was urged to go there by a Muslim Pakistani, Khizar Hayat, whom he met in the United States. The two, according to Iltimas, kept in touch and Hayat invited him to come to Pakistan in 2000.

Workbooks in his suitcase, stored under book shelves and now covered by a coat of dust, show Walker pursued his Arabic studies diligently. In neat Arabic and English handwriting, he wrote lists of Arabic words and phrases and English translations from Arabic recounting the early Muslim battles of the 7th century.

In one book, he lists prayers for different occasions — like eating the day's first meal or entering a mosque — together with sayings of Islam's 7th century Prophet Muhammad.

On the day he left the school — May 15, 2001 — he wrote a brief note in Arabic in the headmaster's diary. "This is Sulayman al-Faris, from Americastan, who learned seven sections of the Quran."