LANSDALE - Joe Maglione 3d, a 22-year-old Marine who took time off from pursuing his dream of designing bridges and buildings to serve his country, was killed this week at Camp Coyote, Kuwait.

"It was his first day there," his mother, Rosemary Corr, said today as Marine officers helped her make funeral arrangements.

She said her son, a Drexel University senior and a Marine Corps reservist, had been activated March 9. After several weeks at Camp Pendleton, Calif., he reached the military staging area in the desert just outside Iraq late Sunday.

The Department of Defense announced today that Maglione, a lance corporal, had been killed Tuesday by a "noncombat weapon discharge." The military said the death was under investigation.

Maglione had been assigned to Bridge Company B, Sixth Engineer Support Battalion, Fourth Force Service Support Group, based in Folsom, Delaware County.

His mother declined to discuss details of his death.

She learned she had lost her only child about 7:45 p.m. Tuesday, when she arrived home from her accounting job in Malvern.

"There were two Marines there," she said. "They were standing at attention" at the front door.

Since then, the mood has been solemn at the home of Corr's parents in this quiet Montgomery County borough.

"This is where Joe grew up," his mother said. "All of his friends are around here. They are all calling."

People at North Penn High School were looking up his picture in the yearbook from 1999, the year he graduated.

Maglione also was being remembered in the Council Rock School District in Bucks County, where he attended school until he transferred to North Penn for his senior year.

Those who knew him said he was a B student who was a sprinter on the track team. He also played football and wrestled.

"He wanted to excel," said Bob Walker, math teacher and track coach at Council Rock High School North. "He worked hard at what he did. He was a very bright young man."

Maglione's mother said her son finished second in an Ironman triathlon held at Parris Island, S.C., during his Marine Corps boot camp.

She said he lived with her and his father until they were divorced in 1985.

After that, Maglione and his mother lived with her parents. The family said his father, Joseph B. Maglione 2d, lives in York.

Corr said her son was a full-time student in architectural engineering.

"He got pulled out two weeks before the end of the " to go with his unit to Kuwait, his mother said.

"I don't want to say too much about what he did over there, but he loved bridges, building them, measuring them," she said. "He has the basement full of models."

For much of today, Corr welcomed visitors to the red-brick twin home, all the while cradling pictures of her son in her arms and showing them to family members and guests.

"The last thing he told me was that he loved me," she said. "And I told him I was very proud of him."

Maglione's friend Jennifer Kozminski, 20, his date for the Marine Corps Ball, was in some of the pictures, and was at the house to offer support.

She said they met during military training. She is in the Air National Guard.

Corr talked about how hard life was with her young son after the divorce and how they pulled together to make it while she got her degree from Temple.

In the afternoon, the mail came, and a family member sorted through it in the hallway by the front door.

He called to Corr. "Here is a letter from Joe," he said.

Corr took the letter carefully in her hands, as if it would crumble if she held it too tightly. It was postmarked the day her son had died.

"My baby. My baby," she sobbed, and went into her bedroom to read it alone.