CNN
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Investigators are trying to piece together how a woman passed through multiple security checkpoints at New York’s JFK International Airport this week and boarded a plane to Paris, apparently hiding in the plane’s restrooms during the flight.

According to the Transportation Security Administration, the stowaway did not have a boarding pass but completed a security screening and bypassed two identity verification and boarding status stations to board a Delta aircraft.

Tuesday’s incident occurred on one of the busiest travel days of the year. Almost 2.7 million passengers traveled by plane that day, before the Thanksgiving holiday, according to TSA data.

Here’s what we know:

According to a TSA spokesman, the stowaway was not carrying any prohibited items.

It is unclear how the person managed to bypass the boarding stations before boarding the plane.

Delta is cooperating with law enforcement and conducting its own investigation, the airline said.

“Nothing is more important than issues of safety,” a Delta spokesman said in a statement. “Therefore, Delta is conducting a comprehensive investigation into what may have happened and will work with other aviation stakeholders and law enforcement agencies to this end.”

CNN has contacted the FBI and Customs and Border Protection for further information.

The stowaway is a woman between 55 and 60 years old and holds a Russian passport. According to an airport official in Paris. She will soon be sent back to the United States, the official said.

The woman is currently in a waiting area at Charles de Gaulle airport – known as ZAPI – for people awaiting deportation because she does not meet the requirements to enter Europe. The woman applied for asylum in France several years ago, the official told CNN.

When asked, the source did not discuss the woman’s mental state.

New York real estate agent Rob Jackson was on the Delta flight when the stowaway was discovered and told CNN that passengers were instructed to remain seated after landing so police could board the plane.

“I didn’t actually see the person in question. “Apparently she was hiding in a bathroom at the back of the plane as we were leaving JFK,” Jackson said. “The first report to passengers that there was a problem was when we were parked at the gate and they told us all to remain seated as the French police would be boarding the plane to deal with ‘a serious security issue’ to take care of.”

Jackson recorded a video of the flight captain saying, “Guys, this is the captain, we’re just waiting for the police to get on board.” They may be here now and have told us to keep everyone on the plane until “We have taken care of the extra passenger that is on the plane.”

The flight was full and there were no additional seats for the stowaway, Jackson said.

“I heard the flight attendants talking to the pilots about it – they said this person was in a restroom and then he would walk out, go to another restroom and stay there for a long time,” he said.

CNN’s Lex Harvey, Holmes Lybrand and Saskya Vandoorne contributed to this report.