Adis Medunjanin, a 28-year-old al-Qaida operative, was found guilty Tuesday of plotting a suicide-bomb attack in New York City subways in 2009. The plot has been described by officials as one of the most serious terrorist plots against America since 9/11.

A jury convicted Medunjanin, a Queens resident, after four weeks of trial. Prosecutors said that plot was aborted after the group learned that law enforcement agents were investigating their activities.

Adis Medunjanin was an active and willing participant in one of the most serious terrorist plots against the homeland since 9/11, Assistant Attorney General Lisa Monaco said in a statement. Were it not for the combined efforts of the law enforcement and intelligence communities, the suicide bomb attacks that he and others planned would have been devastating.

Medunjanin was found guilty of conspiring to use weapons of mass destruction and conspiring to commit murder of U.S. military personnel abroad. He was also convicted for providing and conspiring to provide material support to al-Qaida, receiving military training from the terrorist group, as well as conspiring and attempting to commit an act of terrorism transcending national boundaries, and for using firearms and destructive devices in relation to these offenses.

He will be sentenced on Sept. 7 and faces a mandatory sentence of life in prison. Seven defendants, including Medunjanin, have been found guilty in connection with the New York City bombing plot.

Justice was served today in Brooklyn, as a jury of New Yorkers convicted an al-Qaida operative bent on terrorism, mass murder and destruction in the New York City subways, said U.S. Attorney Lynch. Adis Medunjanin's journey of radicalization led him from Flushing, Queens, to Peshawar, Pakistan, to the brink of a terrorist attack in New York City - and soon to a lifetime in federal prison.

However, Defense attorney Robert Gottlieb disagreed with the verdict and told Fox News that he would appeal. The defense also argued that U.S. agents unfairly coerced Medunjanin and intimidated his family, according to the BBC.

The world and our national government including all our politicians should take note that this is the way crimes should be decided, not in a military commission, not in a star chamber, but in America, he said.

The Justice Department said Medunjanin and his accomplices came within days of executing the suicide bombings in the subway system. It is believed that the men were directed by senior al-Qaida leaders in Pakistan. However, when their plans were thwarted, authorities said Medunjanin tried to kill himself and others by attempting to crash his car on the Whitestone Expressway in New York.

Here's how the Justice Department said that the prosecutors detailed the extent of the training leading up to the aborted terror plot.

Prosecutors found that in 2008, Medunjanin and his co-plotters Najibullah Zazi and Zarein Ahmedzay all agreed to travel to Afghanistan to join the Taliban and kill U.S. military personnel abroad. The group arrived in Peshawar, Pakistan, in late August 2008. However, Medunjanin and Ahmedzay were turned back at the Afghanistan border.

The U.S. government then said that within days the three met with an al-Qaida facilitator in Peshawar and traveled to Waziristan for terrorist training. It was there they met with al-Qaida leaders Saleh al-Somali, who headed al-Qaida external operations. The men also met with Rashid Rauf, who the U.S. government said is a high-ranking al-Qaida operative.

Al-Somali told the men that they would be more useful to the terrorist group and the jihad if they returned to New York to carry out some attacks.

The three were then reportedly given high-powered weapons training In Waziristan. They learned how to use an AK-47, PK machine gun and rocket-propelled grenade launcher, the government stated, and were encouraged to target places that would maximize the number of casualties.

All three men talked about the timing of the attacks and possible targets such as the subways, Grand Central Station, the New York Stock Exchange, Times Square and movie theaters, according to the Justice Department's statement.

When the men returned to the U.S. they agreed to carry out suicide bombings during Ramadan, which fell in late August and September 2009.

Zazi, according to the U.S. government, would prepare the explosives. All three of the men would then carry out coordinated suicide bombings.

Zazi bought large quantities of chemical components for explosives in July and August 2009. On two occasions he checked into a hotel room near Denver to mix the chemicals. Bomb-making residue was later found in that hotel room.

Zazi then drove from Denver to New York on Sept. 8 that year, taking the explosives and other bomb-making materials. But when he arrived he learned that their activities were being investigated, and so the men got rid of the explosives and other bomb-making materials.

Zazi returned to Denver and was arrested on Sept. 19, 2009. Law enforcement agents executed a search warrant at Medunjanin's home on Jan. 7, 2010; Medunjanin later left his apartment and attempted to crash his car into another vehicle on the Whitestone Expressway.

Authorities said Medunjanin called 9-1-1 moments before the impact, identified himself and left a message announcing his martyrdom. They said he shouted an al-Qaida slogan, We love death more than you love your life.

Listen to the 9-1-1 call below: