in September, Townsend said.Related: Petraeus stand-in has been through this before
Broadwell's clearance and rights to view documents could put her in legal jeopardy if she did not follow the procedures.
Under federal law, if Broadwell has classified material in her home she must show she has authority to have it, that it relates to her work in military intelligence and that she is following all security and safety measures to safeguard the material, military officials told CNN.
Broadwell has said that she was working on a second book about Petraeus. Her LinkedIn profile lists her as "Archivist/Biographer for General (Retired) David Petreaus." Her first book, 'All In,' was a look at Petraeus' leadership.
Broadwell has spoken about how she had to deal with sensitive information in the course of researching her first book.
"I had to follow very clear lines of non-disclosure and sign non-disclosure agreements, like my colleagues. I felt like I was almost held to a higher level of accountability because I could lose my clearance," Broadwell said in a speech last year. "I think it was important to inform my writing, but I knew there was a clear line that I couldn't cross when I was writing it out."
Petraeus insists he never shared classified information with Broadwell, said retired military officer John Nagl who has spoken with Petraeus in recent days.
The intertwining of Broadwell's military role and her close access to Petraeus, makes the investigation complicated, said Townsend.
"As a reservist, she had, we're told, top-secret compartmented information clearance. But that clearance is only in place, if you will, active when she's on reserve duty. Clearly when she was embedded with Petraeus, getting ready as his biographer to write a book, that clearance didn't apply," said Townsend.
Townsend said where it gets really complicated is if Broadwell was privvy to information gleaned while being given access while writing the book.
"So she really should not have been given access. And she wouldn't have unless David Petraeus walked her into the room and invited her into these classified briefings," Townsend said. "You know, if the general brings her into a room where there's a classified conversation, you really put the onus then on his subordinates to raise the question of whether or not they can talk in front of her.
"And, of course, they're taking their signal from the general. If he's bringing her in, it's implicit that they're able to speak in front of her. And so I think this is a pretty complicated investigation, both for the FBI and for the Justice Department," Townsend said.
Senior federal law enforcement officials, who spoke on condition of anonymity, told CNN that there is no indication Petraeus disclosed classified material to Broadwell.
The Army refused to publicly confirm the suspension of Broadwell's security clearance, first reported on CNN, but issued a statement:
"The Army has been cooperating with federal law enforcement authorities in this matter, and those actions are ongoing. Appropriate actions with regard to this officer's clearance and access have been taken," said George Wright, deputy director of Army media relations.