WEST CHESTER, Pa. — Nicholas Berg was remembered as adventurous and caring Friday at a private memorial marked by heavy security at a suburban Philadelphia synagogue, friends and family said.

Berg, the 26-year-old whose beheading in Iraq was broadcast on an Islamic militant Web site, was an intelligent and outgoing man whose travels took him from abject poverty in Africa to perilous hot spots in Iraq, friends said.

"You realized what an energetic and talented young man this was, and what a tragedy his death is," said Chester County Commissioner Andrew Dinniman, whose daughter was on a Science Olympiad team with Berg in high school. "On one hand, it was a solemn occasion in which you could hear a pin drop, but it was also a tribute done with poetry, humor and laughter."

The Berg family had urged curiosity seekers, politicians and media members not to attend the memorial. Police said they would turn away and, if necessary, arrest outsiders trying to attend.

Police and sheriff's deputies provided heavy security in and around the synagogue. Visitors were screened with hand-held metal detectors, West Goshen Police Chief Michael J. Carroll said.

Dinniman said about 500 people attended the service, including Berg's friends from high school and college, and past teachers. His father, brother and sister spoke, and the rabbi who presided over the ceremony read words written by Berg's mother.

Bob Concordia, 66, a family acquaintance from West Chester, said "there were some tears, but there were also some laughs. I left with a feeling that he was somewhat of a martyr."

Much of the world reacted in horror to Berg's death and the grisly video that recorded it. U.S. intelligence officials have concluded that terrorist leader Abu Musab al-Zarqawi was the person shown decapitating Berg.

Berg was in Iraq seeking business for his communications company.

Questions continue to swirl around Berg's time in Iraq. The family says his 13-day detention — either by U.S. military officials, according to the family, or Iraqi police, according to military officials — contributed to his death.

U.S. investigators spent at least part of that time trying to verify who Berg was and why he was in Iraq. Also, federal officials said they were looking into Berg's association with a possible terrorist while a student at the University of Oklahoma in 1999. Berg was cleared of any wrongdoing.

Officials say their investigation occurred while he was in Iraqi custody. He was released April 6, and he is believed to have been kidnapped days later.

Berg's body was buried at a Jewish cemetery outside Philadelphia in a private ceremony earlier Friday, a family spokesman said.