FBI calls Sudbury suspect inept but serious terror plotter

Yet, even though Tarek Mehanna, 27, of Sudbury and his friend, Ahmad Abousamra, who allegedly was rejected by the Taliban because of a lack of experience, were portrayed as hapless would-be terrorists in an FBI affidavit unsealed yesterday, federal authorities allege their intentions were deadly serious.

Early yesterday, Mehanna, who was free on bail since his January indictment on a charge of lying to authorities conducting a terrorism investigation, was arrested at his parents’ home on Fairhaven Circle on a new and more serious charge of conspiracy to provide material support to terrorists. Abousamra, who fled Boston for Syria nearly three years ago, was not charged yesterday.

“We don’t want to wait for somebody to become a terrorist before we stop them,’’ Warren T. Bamford, the special agent in charge of the FBI’s Boston office, said by phone yesterday. “We don’t want them to blow something up and kill somebody, because our whole mission is to prevent.’’

He said that anyone who would travel to Yemen, as Mehanna allegedly did in 2004 in search of a terrorist camp that would train him, was a significant concern and had to be taken seriously.

Acting US Attorney Michael K. Loucks said at a press conference that authorities brought the new charge after conducting a lengthy investigation.

“We’re satisfied that we know every member of this group’’ involved in the alleged terrorist plot, Loucks said.

A 55-page affidavit unsealed yesterday alleges that Mehanna, an Internet blogger accused of promoting jihad online, conspired between 2001 and May 2008 with Abousamra and an unnamed cooperating witness to attack a mall, assassinate two members of the US government’s executive branch, and attack US soldiers fighting in Iraq and Afghanistan.

In a statement to reporters outside the federal courthouse yesterday, Boston lawyer J.W. Carney, who represents Mehanna, said: “This is the type of case that challenges our commitment and faith in the United States Constitution. Our country is respected around the world because we presume that people charged with a crime are innocent and we require the government to prove its allegations in open court. I’m confident that the American people will put aside their fears and instead rely on the fairness guaranteed by our Constitution. Mr. Mehanna is entitled to that.’’ He declined to comment further.

Mehanna’s mother, Souad, emerged from the home yesterday and just before leaving in a limousine, said that Mehanna “is a very good guy; he’s innocent.’’

Last November, Mehanna was arrested on a charge that he lied to the FBI in December 2006 when questioned about the whereabouts and activities of Daniel J. Maldonado, a former Methuen resident who was suspected of training at an Al Qaeda terrorist camp to overthrow the Somali government. Mehanna was indicted on the charge two months later, but no trial date had been set.

Maldonado, who is serving 10 years in prison after pleading guilty two years ago in Houston to receiving training at a terrorist camp in Somalia, is cooperating against Mehanna, according to the affidavit unsealed yesterday in Boston.

The affidavit says Abousamra traveled to Pakistan twice in 2002 and 2003 trying to find a jihadist training camp that would take him, but the Lashkar e Tayyiba group would not accept him because he was Arab and the Taliban camp rejected him because of a “lack of experience.’’

Later, Mehanna, Abousamra, and an unnamed cooperating witness allegedly talked about attacks on US soil, including assassinating the two executive branch members, who were not identified by officials, and a mall shooting.

Loucks would not disclose whether a particular mall had been targeted or how far the alleged plot had progressed. The affidavit made no mention of a specific target.

The acting US attorney did not identify the two government officials who had allegedly been targeted, but said they are no longer in the executive branch and “neither were in any danger at any time from Mehanna or his coconspirators.’’

In 2003, Mehanna, Abousamra, and the cooperating witness, inspired by the panic caused by snipers who randomly executed people in the Washington, D.C., area the previous year, “discussed a plan to obtain automatic weapons, go to a shopping mall, and randomly shoot people,’’ the affidavit says.

The cooperating witness met with Maldonado in New Hampshire and asked him to use his gang contacts to get automatic weapons, but Maldonado said he could only get handguns, the affidavit says.

“Because of the logistical problems of executing the operation with just handguns, the plan was abandoned,’’ the affidavit says.

The cooperating witness told investigators that he, Mehanna, and Abousamra wanted to kill US soldiers and others abroad, prompting Mehanna and Abousamra to go to Yemen in 2004 to try to join a terrorist training camp.

The witness said Mehanna later told him that the Yemen trip was a failure because they could not find training camps and everyone involved was in jail or had gone underground, the affidavit says.

In December 2006, Abousamra fled to Syria after being questioned in Boston by the Joint Terrorism Task Force about terrorist activities, the affidavit said.

During a secretly recorded conversation with Mehanna in January 2007, the cooperating witness expressed reservations about what they had done, and Mehanna said “they were hasty and immature, but not wrong,’’ the affidavit says.

Mehanna said he did not regret his trip to Yemen, which “was the best two weeks of his life,’’ the affidavit says.

An FBI analysis of Mehanna’s computer, seized in 2006, found Mehanna “glorified’’ the Sept. 11, 2001, attacks and berated the victims as “sinners,’’ according to the affidavit. The computer contained photographs of Mehanna and others at ground zero, the former site of the World Trade Center towers in New York, “with large grins and Mehanna has one finger pointed up in the air,’’ the affidavit says.

Mehanna’s computer also revealed that he had downloaded numerous pro-jihad videos, as well as a video of the mutilation of the remains of US personnel in Iraq, the affidavit says.

Mehanna, who was born in Pittsburgh and is a graduate of the Massachusetts College of Pharmacy, reacted angrily yesterday when US Magistrate Judge Leo T. Sorokin asked him to stand up while he explained his rights during a hearing at the federal courthouse in Boston.

“I prefer not to,’’ said Mehanna, dressed in black sweat pants, and a black hooded-sweat shirt.

“Fine,’’ Sorokin said.

Mehanna’s father, Ahmed, who was seated in the spectators’ section, shouted to his son, “Stand up!’’

Mehanna jumped to his feet, forcing the heavy wooden chair he had been seated in to crash loudly to the floor. Within minutes, four deputy US marshals rushed into the room to provide additional security.

After prosecutors argued that Mehanna should be jailed until trial, Sorokin ordered Mehanna held without bail until a hearing Oct. 30.

Bamford said the FBI has no information about terrorist cells operating in New England.

But he added, “The home grown terrorists, those individuals who have become radicalized by looking at the Internet . . . are of great concern because those people often fly below the radar.’’

John R. Ellement of the Globe staff contributed to this report. Shelley Murphy can be reached at shmurphy@globe.com.