New York (CNN) Detectives have detained a person as they investigate the death of a woman who was found dead and partially decapitated in a Brooklyn apartment, New York police said.

The body of Savannah Rivera, 20, was found early Saturday after another woman who was in the apartment flagged an Uber on the street and the driver called police, according to a law enforcement official.

NYPD Brooklyn North Deputy Chief Michael Kemper described the incident as a "brutal vicious attack" and said the incident was not random. He said the detained person knew both women.

A motive behind the incident is still unclear, Kemper said, but he said there's a "good possibility" that the case will be categorized as a domestic violence.

An ax recovered from a trash compactor at the public housing complex in the Bushwick neighborhood is part of the investigation, the official said. It's unclear whether the ax was used in the crime.

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