Slain American hostage Nick Berg was an idealistic and adventurous man who supported the US-led war in Iraq, his family members and friends said.
Nick Berg was described as clever and generous
Mr Berg, 26, went to Iraq independently in search of business opportunities for his communications equipment company.
He had previously visited several countries in the developing world in an effort to spread technology.
But his latest trip ended in tragedy when he was kidnapped by Islamic militants and beheaded.
Mr Berg's father Michael told the Associated Press news agency that his son had previously travelled to Ghana, where he taught villagers how to make bricks.
He said his son had given away most of his food while he was there and returned with nothing more than the clothes on his back: "That's the kind of passion we're dealing with here."
William Scott, a close friend from high school days in Pennsylvania, told the New York Times that Mr Berg was "extremely friendly, but also talented and driven".
"He was an adventuresome type and always wanted to help people, even when it was difficult," Mr Scott told the newspaper.
Bruce Hauser, the Berg family's next-door neighbour, remembers the son as being precociously practical.
"He poured a cement sidewalk in his dad's backyard and I don't believe the kid was 12 years old at the time, " he told National Public Radio in the US.
Mr Berg played the saxophone and later the tuba in his high school marching band and was a talented science student.
Henderson High School band director Jim Morrison recalled Mr Berg causing a stir at the annual band camp with a recorded voice message.
"It's a summer camp with summer camp cabins," he told NPR. "Nick rewired his so that when you opened his door it welcomed you to his cabin."
Later, Mr Berg started his own business in West Chester, near Philadelphia, after working for a Texas company that built radio towers.
He first went to Baghdad in December last year against the wishes of his father, who had opposed the war.
"He looked at it as bringing democracy to a country that didn't have it," his father told AP.
He returned to Iraq in March expecting to work for a telecoms company, but decided to leave the country after finding the job was no longer open.
Before he could depart, he was detained in Mosul by Iraqi police on suspicion of using forged papers.
He was freed on 6 April after being questioned by FBI agents, then disappeared.
Nothing more was heard of him until news of his killing emerged.
"We're all just in a state of shock," West Chester mayor Richard Yoder told the New York Times. "He was a well-known, popular kid."
Mr Berg's father said his son's killers may have known that he was Jewish.
"If there was any doubt that they were going to kill him, that probably clinched it, I'm guessing," he said.