Story updated at 5:25 p.m.

The West Essex community where U.S. Army Specialist Derek McConnell grew up called him an “American hero” who was “polite” and “respectful” this week after learning the news of his sudden death.

McConnell suffered life-threatening injuries when he activated improvised explosives while serving in Afghanistan in the summer of 2011. He was on the road to recovery and engaged to be married when he died unexpectedly Monday at the age of 23.

The cause of his death is not immediately known and funeral arrangements have yet to be announced.

North Caldwell Police Sgt. Tom Mautone knew McConnell and his family since he was in grammar school. Mautone said he watched him grow up and they developed a close relationship.

When McConnell was injured, Mautone helped establish the Friends of Derek McConnell, a fund to support the wounded soldier and his family.

"I considered him family," Mautone said. "My heart is heavy for the loss of such a great person and a friend."

North Caldwell Police Chief Mark Deuer said McConnell lived down the street from the police headquarters on Gould Avenue. 

Deuer said a young McConnell would pass the station on the way to and from school, often stopping in to buy a soda from the lobby vending machine and chatting with members of the department.

"We considered him a friend and a hero. He gave his life making sure that we could live in peace here in America," Deuer said.

McConnell graduated from West Essex Regional High School in North Caldwell in 2008. Teachers at West Essex shared fond memories of their former student.

Diana Schoenblum, a mathematics supervisor at West Essex High School, taught him math when he was a sophomore.

“Derek was always very polite and respectful and tried his best in my class,” Schoenblum said Tuesday. “He got along well with his peers. He was a very likeable person.”

Schoenblum added, “I was so sorry to hear about his death at such a young age and I send my sympathies to his family. He was an American hero and a role model to West Essex.”

McConnell was in Caren Maw’s culinary arts class his senior year. Maw said they often talked about nutrition and mixed martial arts.

“In order to perform at his peak, he knew he had to eat well and developed a real interest in nutrition,” Maw said. “That is what we talked about a lot.”

She said he was a quiet young man, “But as we all know, still waters run deep.”

McConnell was a parishioner and former altar server at Notre Dame Parish in North Caldwell. The church posted a message on its Facebook page announcing his death to the congregation.

“Please keep the family in your prayers,” the message reads. “Derek certainly was a fighter and will be missed by all who knew and loved him."

Donations are being accepted in memory of Derek McConnell for his family and fiance at OperationWard57.com.