ABC News sources said that she also had information indicating the possibility of "an attack" on Plum Island Disease Center, a secure US government facility off the tip of Long Island, New York where research into foot and mouth disease, swine fever and other animal pathogens is conducted by the Department of Agriculture and security is provided by the Department of Homeland Security.
"We're proud of our role as America's first line of defense against foreign animal diseases," the facility's website notes. "We're equally proud of our safety record. Not once in our nearly 50 years of operation has an animal pathogen escaped from the island."
The remote possibility of smuggling a pathogen off isolated Plum Island was the subject of the bestseller Plum Island by Nelson DeMille.
But a terrorist attack on the isolated island would not spread disease, according to homeland security officials familiar with the research activities there.
Interest in Siddique is in itself not new. On May 26th, 2004 she became the first woman wanted by the federal government in connection with Al Qaeda when then Attorney General John Ashcroft and FBI Director Robert Mueller asked the public's help in finding her and six men suspected of links to Al Qaeda.
At that same time they warned, in advance of the Democratic and Republican National Conventions, that Al Qaeda was preparing to "hit the United States hard" that summer.
By then Siddique had been linked to an "ill conceived" and perhaps amateurish plot to "kill all living US presidents", according to sources from three federal agencies. And she had already vanished from public view for about 16 months.
She has also been twice married; once to a nephew of 9-11 mastermind Khalid Sheik Mohammed.
Her name reportedly rolled from KSM's lips when he was captured and interrogated by US intelligence officers. She has also been linked to Adnan El Shukrijumah, a pilot and suspected al Qaeda member also on the Ashcroft-Mueller list.
Shukrijumah, Ashcroft noted, had once lived in Florida, had left the United States and had later attempted to re-enter the country using a variety of passports.
"We know that he has been involved in terrorist planning with senior al Qaeda leaders overseas and has scouted sites across America that might be vulnerable to terrorist attack," Ashcroft added.
By the time of Siddique's capture last month, she had become something of a cause celebre among some human rights activists who believe she was "disappeared" five years ago by the Pakistani government, perhaps at the request of the United States.
At a federal court hearing in Manhattan on Monday, the number of supporters who showed up required the US Marshals to move the Magistrate's Court proceeding to a larger courtroom and also open an overflow courtroom where spectators could listen to and watch the proceedings on closed circuit TV.
They saw Siddique slumped over in a wheelchair, the result of having been shot twice with a nine millimeter side arm after she allegedly grabbed a US Army Warrant Officer's M-4 Carbine and opened fire as a team of FBI agents, US Army officers including the Warrant Officer and a Captain, and interpreters prepared to interrogate her on July 18th, the day following her arrest, according the federal complaint.