This still image taken from an undated video published on the Internet by the Islamic State and made available Sunday, Nov. 16 purports to show extremists marching Syrian soldiers before beheading them. (AP)

Federal authorities have arrested and charged a Henrico County, Va., woman who they say wrote Facebook posts supportive of the Islamic State and offered to help someone connect with the terrorist group in Syria, court documents show.

Heather Elizabeth Coffman, 29, is charged with making a false statement regarding an offense involving international or domestic terrorism. Coffman, it seems, was caught in a sting and unknowingly offered to help an undercover FBI agent connect someone with the Islamic State in Syria, according to a federal affidavit. Authorities say she lied to investigators who were looking into her support of the extremist group.

The case seems to be another example of the Islamic State’s robust presence on social media and the influence it is having on Americans. Two months ago, a 19-year-old from suburban Denver pleaded guilty to trying to help the terrorist organization after she tried to board a flight to reach Turkey. She reportedly was trying to connect with a man she met online. And last month, three teenage girls from the Denver area were detained at an airport in Germany and questioned about possibly trying to join the Islamic State. A school official said the girls were victims of an “online predator.”

It is unclear what cultivated Coffman’s interest in the Islamic State or whether she possessed the means to connect anyone with the group.

Mark Henry Schmidt, Coffman’s defense attorney, said the young woman was born and raised in the United States, lived with her parents and cared for her 7-year-old child. He said that he was unaware of any tangible foreign connection, and initially the case seemed to him one of “Facebook going badly.”

“As far as I know she hasn’t traveled anywhere. Her connections with the outside world would be on the Internet,” Schmidt said. “I imagine you can get into trouble on the Internet, but I imagine you can also think a lot more’s going on than really is. If nothing else, this is certainly a cautionary tale about the Internet.”

According to the FBI affidavit, Coffman told an undercover agent that she had previously arranged for a man she termed her “husband” to travel to Turkey so he could meet with Islamic State facilitators and eventually make his way into Syria. She described “concrete steps” she had taken to achieve that, according to the affidavit. But Coffman and the man soon separated and he backed out of the plan, according to the affidavit.

The FBI’s investigation of Coffman seemed to begin in April, as agents took note of her postings on Facebook and sought search warrants to access her various accounts. On June 23, for example, Coffman posted two images with text that included a fuller name for the Islamic State: “We are all ISIS, Islamic State of Iraq & Sham,” according to the affidavit. On June 28, when someone asked why Coffman was expressing support for the group, she responded, “I love ISIS!” according to the affidavit.

Coffman later wrote about persuading her sister to develop an interest in the Islamic State and said, “My dad is a little angry because I got her into all this jihad stuff,” according to the affidavit. A woman who identified herself as Coffman’s mother declined to comment Monday.

An FBI agent posing as someone with views similar to Coffman’s made contact with her in July and, some months later, told her about an associate who wanted to travel to Syria to fight with the Islamic State, according to the affidavit. Coffman offered to help the associate connect with a facilitator and claimed to be able to verify the facilitator’s legitimacy, according to the affidavit.

She told the agent last month that she had done so but that the facilitator was unresponsive, according to the affidavit. She declined to turn over the facilitator’s contact information to the undercover agent, according to the affidavit.

Court records suggest that Coffman suspected law enforcement officials might be monitoring her. At one point, she developed a code system to talk with the undercover agent and at another told the man she said was her husband that the “[National Security Agency] has already seen” his pro-Islamic State Facebook activity. But she apparently was unaware of the undercover agent’s real aim.

On Thursday, two FBI agents interviewed Coffman at her job in Glen Allen, Va., and she denied that the undercover agent had expressed support for the Islamic State or other terrorist organizations, according to the affidavit. It is unclear where Coffman worked.

Court records indicate that Coffman appeared in federal court in Richmond on Monday morning and was ordered held until her next hearing on Wednesday.

Jennifer Jenkins contributed to this report.