The decaying body of a 5-year-old girl was found in a closet inside a Houston apartment – nearly a week after her mother said she died from ingesting chemicals, police said.

Relatives of the unidentified girl made the macabre discovery Monday afternoon at an apartment complex in northwest Houston after noticing a foul odor emanating from a closet.

The girl’s mother, who was at the residence when cops responded, was being questioned by police late Monday. She confessed that her daughter died on Aug. 27 after swallowing chemicals, KRIV reported.

“No matter how the child died, whether it was accidental or an intentional death, you know for a body to be in a closet for several days, it’s just, it’s pretty unthinkable,” Houston police Lt. Larry Crowson told the station. “We’re not sure of the circumstances. We don’t know if it’s an accidental death or an international death, that will be part of the investigation.”

Police said it’s unclear why the girl’s mother did not report her death to authorities last week. The mother admitted to relatives that the source of the nauseating odor inside the apartment was her daughter’s body, which had been “wrapped up,” police said initially, the Houston Chronicle reported.

The relatives stopped by the apartment after not seeing the girl for several days, Crowson told the newspaper. Firefighters later described her body as being in a state of decay and blocked it from the view of witnesses at the scene, according to KTRK.

Houston police confirmed the gruesome discovery in a tweet late Monday. An autopsy is expected to determine the girl’s cause of death.

Messages seeking comment from a police spokesperson and a coroner were not immediately returned early Tuesday.