The quill pen Rembrandt drawing known as The Judgment was stolen from a private art fair and then returned within two days, left at a church. (Gus Ruelas/Associated Press)

Police in Los Angeles are trying to unravel another art mystery after recovering what they thought was an authentic Rembrandt drawing, which had been stolen during an art fair.

The Los Angeles Police Department is now saying that it won’t be returning The Judgment to the Linearis Institute, a public repository for visual arts in San Francisco, until a representative from that organization can answer some questions.

They say they’re unsure about the authenticity and the ownership of the 17th-century sketch, which was part of a private art exhibit featuring work up for sale. 

The drawing is absent from a list of 70 authenticated, signed Rembrandt drawings compiled by expert art scholar Peter Schatborn. Several art historians have also said they don’t believe the piece is by the Dutch master but instead it’s done in the style of the Rembrandt school.

Measuring 28 centimetres by 15 centimetres and dating to 1655, the work was stolen from the Ritz-Carlton Hotel in the beachfront community of Marina Del Rey on Aug. 14. The quill pen and ink drawing, valued at $250,000 US, was snatched from the wooden easel when a curator was distracted by another person.

Police called it a "well thought-out, well-executed theft."

By the following Monday, they were able to recover the piece after it was dropped off at a church in Encino.

Thieves left the work inside the door to the office of Father Michael Cooper at St. Nicholas of Myra Episcopal Church. Cooper, a former L.A. county sheriff’s deputy, said the action was in keeping with the fact that a church is "a place of reconciliation."

Police say they believe the thieves may have panicked after the case got worldwide attention.

Rembrandt is widely regarded as one of the finest painters in European art history and his worldwide name recognition has made his work a common target for thieves.