Christine Von Der Haar has heard President Barack Obama and national security officials insist the U.S. government isn't spying on ordinary citizens.

The Indiana University faculty member doesn't believe them. Not after what happened to her at the Indianapolis airport.

Von Der Haar says in a federal lawsuit that she was illegally detained by U.S. Customs and Border Protection agents in 2012 at Indianapolis International Airport. The lawsuit says the detention occurred after government agents intercepted and read emails she had exchanged with a friend from Greece before he came to visit her in Indiana.

While her lawsuit says the detention violated the U.S. Constitution's Fourth Amendment, which protects against unreasonable searches and seizures, Von Der Haar said that issue cannot be separated from what she believes was illegal and unjustifiable spying.

The case is the latest example of questionable conduct that highlights growing concerns over the government's secret monitoring of personal telephone and other electronic communications, tactics the administration says are necessary in the fight against terrorism.

The monitoring, exposed by former National Security Agency contractor Edward Snowden, is now under review by the White House, the intelligence agencies and Congress as they weigh significant changes in the way the programs are run.

"We are having this debate in the United States, and this is a case that shows, without a doubt, that emails were read," Von Der Haar explained.

"If I don't come forward and say, 'Yes, it did happen,' I think other people are just going to sweep this under the rug and pretend like people are making a whole lot out of nothing."

Hanni Fakhoury, staff attorney for the nonprofit watchdog Electronic Frontier Foundation, said the government has no business investigating the personal, intimate relationship between two adults.

"Based on what's alleged in the complaint, there seems to be very little reason why the government was reading emails between these two people," he said.

"With all of the controversy surrounding electronic surveillance, accusations like this certainly cause quite a bit of doubt about the government's repeated assertions that it doesn't collect information about American citizens on American soil and isn't intruding on people's private lives."

The U.S. Customs and Border Patrol did not respond to messages seeking comment from The Indianapolis Star.

Von Der Haar, a lecturer in IU's sociology department, was detained at the airport after she accompanied her friend, Dimitris Papatheodoropoulos, to pick up computer equipment he had shipped to Indianapolis.

Her friend is a Greek national who has worked as a transportation manager for two Olympic Games and the 2011 Arab Games in Qatar.

The customs agents, the lawsuit says, asked the couple if they were planning to marry, then questioned each separately about email communications and the nature of their relationship.

During that questioning, Von Der Haar was confined in a guarded room for more than 20 minutes with no explanation of why the agents wanted to talk with her.

The only way the federal officials could have known about some of the information they questioned Von Der Haar about, according to the lawsuit, was to have "surreptitiously monitored the communications" between the IU lecturer and her friend.

One of the customs agents, the lawsuit alleges, "admitted that employees of the United States had read email communications" between the two longtime friends.

"I was a nervous wreck. I didn't know what happened," Von Der Haar said of the airport incident. "Nothing made any sense at all. Nobody explained anything."

Von Der Haar said she suspects the snooping was triggered by Papatheodoropoulos' work in Qatar. But no one from the government has ever attempted to explain or apologize.

"To this day," she said, "I still don't know what it was about."

The harrowing experience turned Von Der Haar, 60, Bloomington, away from the Internet and email.

"I use the Internet very little now," she said. "I've gone back to the way we all lived back in the 1970s, which is fine for me. It's just wondering about who's reading my email and why."

The American Civil Liberties Union of Indiana filed the lawsuit Wednesday on behalf of Von Der Haar in U.S. District Court for the Southern District of Indiana in Indianapolis.

"This case raises troubling issues about the power of the government to detain and question citizens," said ACLU of Indiana Legal Director Kenneth Falk.

Falk said law enforcement agents are free to question someone voluntarily but cross the line "the minute a reasonable person would not perceive they are free to leave."

In Von Der Haar's case, the lawsuit says, the agents appeared to be armed with weapons and blocked the door to the room where she was being questioned. At that point, Falk said, the agents' actions became an illegal seizure - even if she was detained for only about 20 minutes.

"Her companion was taken away for five hours without an explanation," Falk said, "and she is asked questions that are both intrusive and concerning with no indication how or when she could leave."

Von Der Haar's friend was never charged, though customs agents did temporarily confiscate his passport.

They also provided Papatheodoropoulos a notice that a proceeding was being initiated for his removal from the U.S.

It stated, in part: "You obtained your B1/B2 visa by misrepresenting your intentions to come to the United States to wit; It is your intention to immigrate to the United States, you abandoned your foreign residence, you intend to overstay your admission to the United States."

The lawsuit says those allegations - leveled against the man just days after he arrived in the U.S. on a visa that did not expire until May 2, 2022 - were not true, and federal officials did not proceed with the removal action.

Falk said he has no idea whether the situation was a one-time thing or part of a broader pattern.

Falk said the allegations that government agents read Von Der Haar's emails also are problematic.

"We are obviously concerned about that," he said, "but we just don't know enough about what happened, so at this time we are only focusing on her seizure."

Shawn Boyne, a professor at the Indiana University Robert H. McKinney School of Law in Indianapolis, agreed that the monitoring of Von Der Haar's emails is troubling.

"I'm puzzled by what the suspicion was other than some alleged misrepresentation" on a visa application, she said.

Government monitoring of communications between private individuals is supposed to be limited to issues related to terrorism and violence, Boyne said, "not potential technical violations of a visa application."

A USA TODAY/Pew Research Center Poll last month indicated that 70 percent of Americans say they shouldn't have to give up privacy and freedom in order to be safe from terrorism. Most also think there aren't adequate limits in place to what the government can collect.

Star reporter Bill McCleery contributed to this story. Call Tim Evans at (317) 444-6204. Follow him on Twitter: @starwatchtim.