A fetus was found in the bathroom of an out-of-service American Airlines plane early Tuesday at LaGuardia Airport in New York City, a police source confirms to PEOPLE.
The remains were discovered by cleaning staff aboard the aircraft, which had flown in from North Carolina on Monday night, according to the N.Y.C. police source.
Further information about what happened to the fetus was not immediately available.
In a brief statement to PEOPLE, the N.Y.C. medical examiner’s office confirmed only that they were investigating the situation and that more information would be released when the investigation finished.
“As we continue to learn more about this tragic and sensitive situation, we are actively cooperating with law enforcement in their investigation,” an American Airlines spokesman said in a statement to PEOPLE.
A spokesman for the Port Authority of New York & New Jersey, who has jurisdiction over LaGuardia, referred questions to prosecutors in Queens, who did not immediately return a request for comment.
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A source with knowledge of the incident, who asked not to be identified given its sensitivity, tells PEOPLE the fetus was discovered during routine maintenance, cleaning and other inspections after the plane arrived from Charlotte on Monday.
The aircraft, an Airbus A321, was scheduled to fly back out on Tuesday but will remain out of service, the source says.
LaGuardia appeared to tweet about the case early Tuesday, warning travelers that “American Airlines flights at Terminal B may experience some delays due to an out of service aircraft. Please check with @AmericanAir before your departure.”
In a followup tweet about 9:45a.m., the airport wrote that the plane “has been cleared.”