The Chicago man accused of helping organize the bloody November 2008 terrorist attacks that left 166 people dead in the Indian city of Mumbai pleaded not guilty to terrorism charges.
He will head back to court on Jan. 12 for a status hearing.
This is the second terrorism charge for David Coleman Headley, who was also implicated in a scheme to bomb a Danish newspaper over a set of cartoons that depicted the prophet Muhammed in an unflattering light.
The charge of conspiracy to bomb public places in India that resulted in death carries a possible death penalty on conviction.
Headley is said to be cooperating with federal prosecutors.
Among the victims in the Mumbai bombing were a Virginia man, Alan Scherr, and his 13-year-old daughter, Naomi.
Scherr's widow, Kia, says her husband had gone to Mumbai to scout locations for a meditation retreat.
Kia Scherr said in a statement monday that the FBI had informed her of the charges against Headley. She says she hopes he "cooperates fully and discloses all information" to aid in the investigation.
Meanwhile, FBI officials are en route to Pakistan to investigate another link to this bombing. They plan to interview retired Pakistani Army officer Abdur Rehman Hashim Syed, who is in custody in that country in connection with the attacks.
The U.S. charges said Headley, who changed his name from Daood Gilani, had attended militant training camps in Pakistan and conspired with members of the Pakistan-based militant group Lashkar-e-Taiba to launch terrorist attacks in India.