A man who believed he was assisting members of Al-Qaeda in a plan to launch bombs at several Metrorail stations in Washington was arrested this week, according to the U.S. Justice Department.

After Farooque Ahmed, 34, of Ashburn, Va., was taken into custody Oct. 27, officials alerted the public and Metro system workers that they were never in danger, as the officials – which included the FBI – had been well aware of Ahmed’s activities prior to the time he began his attempt. They also said that Ahmed had been closely monitored up until the time of his arrest. If convicted, Ahmed faces a maximum penalty of 50 years in prison.

“Today’s case underscores the need for continued vigilance against terrorist threats and demonstrates how the government can neutralize such threats before they can come to fruition,” Davis Kris, assistant attorney general for national security, said in a statement. “Farooque Ahmed is accused of plotting with individuals he believed were terrorists to bomb our transit system, but a coordinated law enforcement and intelligence effort was able to thwart his plans.”

The Pakistan-born Ahmed is a naturalized U.S. citizen. According to the FBI, a three-count indictment against him includes an attempt to provide material support to a designated terrorist organization, collecting information to assist in planning a terrorist attack on a transit facility and attempting to provide material support to carry out multiple bombings to cause mass casualties at D.C.-area Metrorail stations. If convicted, Ahmed faces up to 50 years in prison.

U.S. Sen. Benjamin L. Cardin (D-Md.), chairman of the Senate Judiciary Terrorism and Homeland Security Subcommittee, said in a statement the day of Ahmed’s arrest that the Metro system is part of a critical infrastructure that allows federal employees – including many Marylanders – to travel safely to and from work on a daily basis.

He said Metro riders had received a fresh reminder that there are still individuals and organizations who seek to do harm to others.

“But our law enforcement and intelligence agencies are working around the clock to prevent and disrupt potential attacks in the United States,” Cardin said. “I commend the FBI for taking action to stop a plot by an individual who believed he was working with a terrorist organization to plan multiple bombings and cause mass casualties at Metro stations.”