An American woman traveling in Europe has been arrested after allegedly tossing her newborn out of a hotel window in Paris, resulting in the infant’s death, as reported by authorities on Tuesday.

Investigators from child protection services are treating the incident as a homicide involving a child under the age of 15. They are also exploring the possibility of a condition known as pregnancy denial, where a woman may not realize she is pregnant until she gives birth.

On Monday morning, the baby was allegedly thrown from the second-floor window of a hotel, according to the Paris prosecutor. Emergency medical teams quickly transported the infant to the hospital; however, the baby was later pronounced dead.

The mother, who was on a journey across Europe with a group of peers from the U.S., received medical attention at a hospital after giving birth and is currently being held in custody there, according to officials.