Early in his prep school days in Baltimore, Nick Ziolkowski decided that he wanted to go into the military, and he pursued that ambition with a steadfastness that the other students wished they shared.

"Every other kid envied him his clarity," said Ab Logan, who taught English to Ziolkowski in his senior year at Boys' Latin School. "It was his sense of purpose that just made him everybody's hero."

The death of Marine Corps Lance Cpl. Nicholas Lee Ziolkowski, 22, of Towson, Md., "in support of Operation Iraqi Freedom," was announced yesterday by the Defense Department.

The Pentagon provided no details. Ziolkowski's father, Andrew, of Germantown, said in a written statement that "it is believed that as a team leader and scout sniper, Nick led his squad into heavy combat before he was lost" in the assault on Fallujah.

The father wrote that his son's captain "wanted ten more guys like Nick. He had the patience, temperament and fortitude to do the job."

In school, Ziolkowski captained the cross-country team in 2000 and had been on the swimming team, cross-country Coach Bill Pheil said.

English teacher Logan described Ziolkowski as a "generous, fun, warmhearted kid," distinguished by the sense of purpose that "just lit him on fire" and drove him to "push himself academically and physically."

Based on journals he kept, Ziolkowski, whose father said he intended to come home next year and attend college, "could have been a writer," Logan said.

The father also quoted Nick's brother Peter as saying that Nick and a friend "dreamed of going to Cancun [in Mexico] and opening a surf shop."

Ziolkowski "was a true hero," his brother Peter said in the statement. "I lost a good and kind brother."

Ziolkowski's survivors, in addition to his father and brother Peter, include his mother, Tracy Miller of Towson, another brother, Alex, a sister, Julia, and a grandmother.

The father said in his statement that his son "began planning for his military service when he was in ninth grade. He ran for miles every day and worked out constantly to get himself in the best shape possible."

Nick enlisted after his 2001 graduation from Boys' Latin. He was in the 1st Battalion, 8th Marine Regiment, 2nd Marine Division, 2nd Marine Expeditionary Force based at Marine Corps Base Camp Lejeune, N.C.

"Nick joined the Marines firmly believing he could help make the world a better place," his father said in the statement.

He said services would be held at Arlington National Cemetery on Nov. 24.