Friends of 22-year-old Dustin Libby, a Marine from the Aroostook County town of Castle Hill who was killed in Iraq last week, are shocked by his death, his brother said Saturday.

"They're all really shook up over the loss," said Chris Libby, adding that the family has received a stream of phone calls and e-mails from Dustin's friends, along with condolences from public officials including Sen. Olympia Snowe and Gov. John Baldacci.

"It's gotten out more and more. It's official now," he said. "We've had more calls and more support today."

Cpl. Dustin J. Libby, 22, died Wednesday while manning a rooftop machine gun during a firefight in Anbar province, Chris Libby said. A member of Cpl. Libby's squad told Chris Libby of Mapleton that his brother went down still holding the trigger.

Libby was one of seven Americans killed in combat Wednesday in Anbar province. "Libby was a hero and a terrific young man. He will be sadly missed," Gov. John Baldacci said in a statement released Saturday. "I spoke with his family earlier today and our hearts and prayers go out to them and all who knew this man who died while serving his country. He represents the best in Maine."

Libby was assigned to the 2nd Battalion, 4th Marine Regiment, 1st Marine Division, I Marine Expeditionary Force, and was based at Camp Pendleton in California. He was just two weeks into his second tour of duty when he died.

U.S. Sen. Olympia Snowe, R-Maine, also issued a statement on Saturday: "Dustin Libby was a true American hero and his service and sacrifice is an inspiration to us all. My thoughts and prayers are with his loved ones during this most difficult time. We must never forget the tremendous contribution our servicemen and women make in defense of our nation."

His brother said Saturday that the family still had no official word on the circumstances surrounding Libby's death. Chris Libby said his family had not foreseen that Dustin Libby would enter the service. His brother described him as a hellion who had been impressed by how a buddy had been transformed by his experience in the Marines.

There had been talk of invading Iraq for months before Dustin Libby signed up for the Marines.

The day he signed the papers, his brother picked him up and they went home to turn on the TV set and see President Bush announcing the invasion.

"I looked at him," Chris Libby said, "and he said, 'Well, I knew we were going there.' " Chris Libby said his brother made it through some tough scrapes on his first tour and was "scared half out of his mind," but he had no regrets.

He recalled how his younger brother looked the day he shipped off for boot camp -- a kid with scruffy, long hair, still a bit tipsy from the previous night's festivities. When the brothers saw each other again at boot camp graduation, Chris Libby did a double take.

"I'm looking at this man in front of me. I'm two inches taller than him and he's looking at me, eye to eye, in full uniform. It amazed me," Chris Libby said.

"They talk about it on the advertisements on TV: We'll take your children and we'll turn them into men. He came back a man. He came back more than a man; he came back a Marine."

The family is still making arrangements for the funeral. Dustin Libby's survivors include his mother, Geni Libby of Castle Hill; his father, Judson Libby of Caribou; and his brother. Dustin Libby was engaged to Jeannine Gonzales, whom he met in California and planned to marry when he returned from Iraq.