Within the last week, authorities say, Amine El Khalifi's plan to wreak havoc was proceeding as hoped: An al-Qaida associate handed him an automatic weapon to kill security officers inside the U.S. Capitol. A bomb-laden vest would detonate the building. He would die as a martyr.

But there was a problem: The explosives were inert, the gun inoperable and the supposed al-Qaida member was actually an undercover officer, according to court documents.

El Khalifi was arrested Friday in a parking garage on his way to carry out an attack the FBI says he kicked around for months, even detonating a practice bomb in a quarry, all with varied targets in mind.

An FBI affidavit traces the evolution of the plot from a vague plan to prepare for the "war on Muslims" to more clearly articulated visions of attacking a restaurant and synagogue to, finally, a goal of obliterating the seat of American government. The document alleges a weeks-long flurry of final activity by El Khalifi, monitored by the FBI and coordinated through an undercover agent, to scope out the building, train in explosives and arm himself for a suicide attack.

As El Khalifi, 29, was making a court appearance Friday on a terrorism-related charge, the FBI executed search warrants inside a gated residential community in Alexandria and at a red-brick rambler in Arlington, though it wasn't immediately known what they found.

El Khalifi is scheduled to have a bond hearing Wednesday. A public defender at El Khalifi's initial appearance didn't return a phone message Saturday. If he is indicted and convicted, he could face life in prison.

Authorities have released only basic biographical details about El Khalifi and haven't described how they believe he became intent on destruction. He was born in Morocco and came to the United States in 1999, when he was 16, overstaying his visitor visa and remaining in the country illegally, court papers say. He is unemployed and is not believed to be associated with al-Qaida.

In 2010, he aroused the suspicion of a former landlord, Frank Dynda, who leased him a one-bedroom apartment inside a brick building in Arlington before ultimately evicting him for not paying rent. He said El Khalifi lived with a woman, whose name was used to secure the lease. Dynda recalled the woman as Bulgarian and said he was under the impression they were married.

She had a job, but El Khalifi appeared not to have rent money.

"She looked good on paper. He looked terrible on paper," Dynda said.

Dynda said El Khalifi periodically received heavy boxes labeled "Books" from Baltimore and advertised his apartment as some sort of luggage business, though Dynda said he never saw any luggage there. The woman moved out, and two or three other men resembling El Khalifi began staying there, Dynda said. The rent checks stopped coming.

Dynda confronted El Khalifi for being a squatter, but he said El Khalifi told him he had a right to be there and threatened to assault him. Dynda called police, but he said officers advised him to treat El Khalifi like a legal tenant. He moved out that summer.

"He was going to harm me, and I think I'm very lucky to be alive today," Dynda said.

The investigation that led to El Khalifi's arrest started last January on a confidential informant's tip to the FBI. The informant described a meeting inside an Arlington apartment, where a person who produced an AK-47, two revolvers and ammunition said the war on terror equated with a "war on Muslims" and urged the group to prepare for battle. El Khalifi, the FBI learned, expressed agreement.

The FBI doesn't believe he was conspiring with anyone else, and court documents in El Khalifi's case don't give further details about the meeting in the Arlington apartment and the other people who were there. Police are investigating others with whom El Khalifi associated, but not because they believe the associates were part of a terror conspiracy, a counterterrorism official has told The Associated Press.

By December, authorities say the sting operation and El Khalifi's own plans were taking shape.

That month, he traveled to Baltimore with a man he knew as Hussien to meet a person who was introduced to him as an al-Qaida associate, authorities say. He told the man, Yusuf, that he planned to blow up a building just outside Washington in Alexandria, Va., that contained military offices. Handling the man's AK-47, he spoke of wanting to "use a gun and kill people face to face," according to the complaint.

Unbeknownst to El Khalifi, the man who called himself Yusuf was an undercover law enforcement officer. Hussien was an operative working undercover with investigators.

As the meetings continued, the plans evolved.

El Khalifi spoke in December of wanting to attack a synagogue and Army generals. But within days, he was settling on a new plan to bomb a Washington restaurant at lunchtime after a waiter told him that was the busiest time, the affidavit says.

On Jan. 8, in preparation for the restaurant attack and a planned al-Qaida attack on a military installation, authorities say he bought two jackets and a cell phone. He agreed to buy more phones, nails and glue to use in bomb-making and said he would be happy killing 30 people, authorities say.

He changed his mind a week later, saying he wanted to blow himself up inside the Capitol as an act of martyrdom and selected the date of Feb. 17, prosecutors say. He went on something of a test run on Jan. 15, using a cell phone to detonate a test bomb at a West Virginia quarry. But instead of being satisfied with the explosion, the FBI says, he wanted a bigger bomb and more damage.

Court papers show the last two weeks were consumed with the planned attack on the Capitol. El Khalifi selected a location to be dropped off. He asked that even more explosives be strapped to his body. He wanted to ensure the bomb in his vest could be remotely detonated in case he faced security problems, authorities say.

The final planning happened in an Alexandria hotel room on Valentine's Day, when authorities say "Yusuf" handed El Khalifi an automatic machine gun and showed him a jacket that the suspect thought contained a bomb, the affidavit says. El Khalifi studied himself in the mirror with the weapon. He practiced shooting it. He discussed how he would be identified in a video al-Qaida would release after the attack.

By Friday, the plans were firms.

El Khalifi got into a van in northern Virginia with Yusuf and Hussien. The gun and vest he had asked for were inside. The van pulled into a parking garage near the Capitol. El Khalifi got out alone in preparation, investigators say, to carry out his plot.

Before he could leave the garage, he was arrested.