A New York-based Pakistani man with possible ties to an alleged Sept. 11 (search) mastermind may face terrorism-related charges, Fox News has learned.

Uzair Paracha has been held as a material witness since being arrested at his workplace by the FBI nearly four months ago. Federal authorities have not made his arrest public.

The case against Paracha is currently under seal. However, sources close to the case told Fox News that the FBI’s joint terrorism task force turned their attention to him based on his possible ties to Al Qaeda (search) and his work in the shipping industry.

Authorities do not believe the company that employed Paracha is connected to Al Qaeda or terrorism-related activities. They are also not certain if he was actually plotting attacks in the United States or abroad, one source said.

However, the source also said, authorities do believe Paracha may have been closely connected to Khalid Shaikh Mohammed (search), Usama bin Laden’s senior operational commander. Mohammed, who was captured in Pakistan last spring, is suspected of having organized the Sept. 11 terrorist attacks. U.S. authorities also believe he smuggled or attempted to smuggle Al Qaeda operatives into the United States even after the attacks.

The pending charges against Paracha may include providing material support to terrorists. But a final decision on formal charges has not yet been made, sources said.

Meanwhile, Paracha's father, who also works in the shipping industry, is in U.S. custody as well. Saifullah Paracha runs a clothing export business in Pakistan that ships goods to the United States.

While much attention has been paid to tightening airline security in the wake of the 2001 attacks, the U.S. maritime and shipping industry has yet to enact similarly strident measures due to logistical and monetary tensions. Final rules implementing Congress’ Maritime Transportation Security Act, passed last year, will likely be released sometime in October.

If charged, Paracha would be the latest catch in a series of U.S. attempts to prevent any “second wave” of terrorist attacks.

Iyman Faris (search), a 34-year-old trucker from Ohio, pleaded guilty to two felony terrorism charges in late June. A native of Kashmir who became an American citizen in 1999, Faris received instructions directly from senior Al Qaeda leaders, including Mohammed, to derail trains and disable major bridges as part of a follow-up wave of attacks on the United States.

Mohammed, who is in U.S. custody overseas, has told interrogators he ordered Zacarias Moussaoui (search) to prepare a second round of attacks to follow Sept. 11.

Moussaoui, a French citizen and self-described lieutenant of Al Qaeda, is the lone defendant charged with crimes related to the attacks on the World Trade Center and the Pentagon that killed more than 3,000 Americans.

Fox News' Anna Stolley, Jane Roh and The Associated Press contributed to this report.