A Metro article Tuesday characterized researcher Steven Emerson as "pro-Israel." Emerson acknowledges that critics have described him as pro-Israel, but he describes himself as a neutral journalist and author who specializes in the subject of terrorism. (Published 8/10/95)

During the two years he lived on a quiet Falls Church cul-de-sac, Mousa Abu Marzook left few of the tiny fingerprints created by the typical suburban life.

Residing in a rented two-story home in the early '90s with his wife and six children, he apparently had no local driver's license, paid no personal property taxes and said so little to his neighbors that their most vivid memory of Marzook was his cutting the grass from time to time.

The few tidbits that neighbors gleaned only deepened their curiosity about the man who lived among them in the 5800 block of South Sixth Street. A business card said he ran a company out of his home but gave no hint of its services. He traveled often, working on business projects that were a mystery to even his closest associates.

Then, on July 25, Marzook's obscurity abruptly ended. He was arrested at John F. Kennedy International Airport, accused of possible terrorist activity, as he tried to reenter the United States. In the days since his arrest, friends and foes have painted the blank canvas he created in the United States with radically different portraits.

Federal immigration officials, relying in part on information from the Israeli government, which is seeking to extradite Marzook on terrorism charges, say he quietly helped mastermind a radical Palestinian organization from Northern Virginia, often using a Springfield think tank as a cover.

Supporters vehemently deny that Marzook sponsored terrorism, portraying him as an influential moderate whose arrest could derail any hopes for a lasting peace.

But on one point all sides agree: Marzook used his time in the United States to become a leading figure and fund-raiser for the Islamic Resistance Movement, also called by its Arabic acronym Hamas, a group that has acknowledged its involvement in suicide bombings and other attacks on Israeli citizens and soldiers.

Although he was virtually anonymous in Northern Virginia, even in much of the Muslim community, Marzook, 44, moved freely among Middle Eastern capitals, and his actions and words were followed closely by Arab and Israeli leaders.

"My client has met with heads of state," said Stanley Cohen, his attorney. "Israel and the U.S. know that this is not a guy toting guns or ordering hits. He is a major political force in the Middle East."

The Marzook case underscores a continuing debate over how great a threat is posed by radical Islamic groups based in the Washington area and other U.S. communities.

The United States' Muslim population swelled during the 1980s as refugees fled violence in the Middle East and Central Asia. Federal law enforcement officials say Hamas and other radical groups have established a vibrant support network in this country that is only a fax away from the front lines.

"Even though the U.S. is the Great Satan in many of their minds, they have also found this is a place they could have assemblies, publish brochures, even collect guns and train people," said Oliver B. Revell, a retired FBI official who directed the bureau's counterterrorism effort from 1982 to 1991. "All these things they could do in the United States, and nobody paid attention."

Others, both inside and outside the U.S. Muslim community, say the role of American Muslims in Middle East radical groups is wildly overblown, arguing that Palestinian terrorist networks are extremely diffuse and have little need for direction, or even large amounts of money, from abroad.

"People think the FBI is pushing a witch hunt on Muslims," said Mustafa Malik, an opponent of radical Islam who is writing a book on U.S. Muslims. "Accusing a person of terrorism because they are a member of Hamas is very misleading. Hamas is doing other things, too."

Through most of his time in the United States, there was little to suggest that Marzook would merit notice, let alone notoriety.

Born in Gaza, Marzook studied engineering in Cairo and, after graduating about 1975, went to work as a petroleum engineer in the United Arab Emirates.

By his twenties, Marzook had become increasingly interested in Palestinian autonomy from Israel. It is not certain when he first came to the United States, but diplomatic and other sources suggest he arrived in the late 1970s.

Starting in the early 1980s, he was actively involved in a group called the Islamic Association for Palestine, which served as a "nucleus for radical Islamic-oriented Palestinians" in this country, according to Steven Emerson, a pro-Israel researcher and author who has studied Islamic networks in the United States.

After receiving a master's degree in industrial sciences at Colorado State University, Marzook in 1985 moved his family to Ruston, La., where he began a doctoral engineering program at Louisiana Tech University. Although Marzook would call himself a student at Louisiana Tech for the next eight years, he often fell behind in his work and received incompletes for classes he missed, school officials said.

"I'm surprised he's such a big leader. He didn't show the leadership here," said a professor of industrial engineering at Louisiana Tech, one of Marzook's advisers who asked that his name not be used. "He was not a bright student."

But Marzook's academic research -- focusing on the use of bar codes -- was not his only interest. He became active in the Islamic Center of North Louisiana, a prayer and social organization, and routinely traveled to the Middle East, the professor said.

That pattern of frequent travel continued after Marzook moved to the Falls Church house in 1990 or 1991, purportedly as part of a private business he ran.

"The man was never in the house, almost. He always traveled," said Reimei Kao, who has owned the house with her husband for 15 years. Marzook told the couple he had a company in Annandale that would pay his rent when he was out of town. Kao declined to name the company.

On a business card several years ago, Marzook listed himself as chairman of a company called Mostan International Inc. The company's address was the same as his home in Falls Church. Mostan was not listed in the telephone book and was not registered to operate in Fairfax, according to county records. It also was not listed in state records of corporations authorized to do business in Virginia.

His attorney said Marzook, who received his green card in a 1990 visa lottery, was in the construction business and held property investments in Los Angeles as well as a small holding in a Southwest computer company. "It's not been a priority of mine to figure out all his businesses, but I'm sure he is squeaky-clean," Cohen said.

One of Marzook's few professional associations was to serve on the board of the United Association for Studies and Research, a Springfield think tank that has been branded by Israelis as a Hamas front.

Ahmed Yousef, the association's executive director, who met Marzook while also studying engineering at Colorado State, said he knew Marzook as a successful businessman who agreed to promote the think tank during his Middle East travels. But Yousef, who said his think tank has no ties to Hamas, was unable to describe the nature of Marzook's business.

Marzook's time in Northern Virginia ended in late 1992 or early 1993, when a series of events brought his role with Hamas out in the open. After the slaying of an Israeli soldier by a loosely organized band of youths, Israel deported 425 Palestinians labeled as Hamas supporters.

In January 1993, a Chicago area businessman, Mohamed Salah, was arrested in Gaza, accused by Israeli officials of delivering cash to Hamas terrorists. Shortly afterward, Israeli officials mounted a public campaign against Marzook and the United Association for Studies and Research, saying Salah had made statements to his captors alleging that both had actively directed Hamas field actions from afar.

The case has stirred intense controversy among Arab activists, who say that Salah was framed while carrying out peaceful activities and that he named other innocent parties, including Marzook, to save himself.

But the turmoil caused by the two events apparently convinced Marzook to leave for Jordan. Abdurahman Alamoudi, president of the American Muslim Council in Washington, said Marzook told associates that he did not want his Hamas connections to embarrass fellow American Muslim leaders.

Yousef said the attacks on Marzook are an Israeli fabrication, possibly to keep Hamas out of any Mideast dialogue.

"If this guy is a terrorist, there are no moderates," Yousef said. "He is like {Yasser} Arafat with the PLO. He can take risks" in exploring unpopular peace initiatives, he said, referring to the Palestine Liberation Organization leader.

Once in Jordan, Marzook openly emerged as leader of Hamas's political wing. The Hamas political wing operates camps, hospitals and other social services in Gaza. Cohen denies that Marzook had any knowledge of terrorist activity.

In late 1992, Marzook was received openly in Tehran by top Iranian leaders, and in April 1994, Arafat even complained to a group of American visitors that Marzook was disrupting the Palestinian peace process by meeting covertly with U.S. officials. The United States officially has refused to meet with Hamas since the 1993 World Trade Center bombing, because of the group's terrorist actions.

Leaders in Israel reject the purported division between Hamas's political and terrorist activities, saying in its request for extradition that Marzook repeatedly sent agents to Israeli-occupied territories to provide funds and orders for violence.

"The political wing does not tell the exact targets, but they set the policy," said one Israeli source, who asked not to be identified, adding that attacks are timed consciously to disrupt negotiations between Israel and the PLO. Staff researcher Robert Thomason contributed to this report. CAPTION: Since his July 25 arrest on terrorism charges, friends and foes have painted starkly different portraits of Mousa Abu Marzook.