The theft was resolved in less than a week, but the mystery remains: Who stole two Carolee Schneemann photographs from MoMA PS1, only to mail them back a mere four days later?

The artworks, worth $55,000 and $50,000 each, according to the New York Post, were discovered missing from the exhibition “Carolee Schneemann: Kinetic Painting” (on view through March 11) by a facilities manager around 11 a.m. on Monday, October 30.

That Friday, the museum received a oversize package. Inside were the missing gelatin-silver prints, taken by Alex V. Sobolewski to document Schneemann’s nude performance art. There was no note, and it remains unclear whether the thief had a change of heart or the works were returned by a third party.

Carolee Schneemann, Eye Body #1 (1963/1985). Two other nude photographs of the artist taken by Alex V. Sobolewski were stolen and later returned to MoMA PS1. Courtesy of the artist, P.P.O.W, and Galerie Lelong, New York.

Police investigated the shipment and uncovered surveillance footage from the previous evening at Office 11211, a shipping store in Williamsburg, Brooklyn. The video, a 20-second clip released by the police, shows a woman in a dark knit hat, glasses, tan pants, and a black coat arranging to send the package to the museum.

Anyone who might have insight into her identity are being asked to contact the police, who are investigating the matter. If connected to the theft, the suspect could face charges of criminal possession of stolen property and grand larceny, according to authorities.

This woman was caught on surveillance tape mailing two stolen photographs back to MoMA PS1. Screenshot courtesy of the NYPD.

The two works are titled CS in the broken mirrors on the back of Four Fur Cutting Boards (1965) and CS With Gloves (Radiator), 1965, on loan from the artist and New York galleries P.P.O.W. Gallery and Galerie Lelong.

A press representative for MoMA PS1 declined to comment on the ongoing investigation. There was no sign of forced entry, and the security alarm, while activated, never went off.

UPDATE: This story originally cited a CBS report that incorrectly claimed that PS1 does not have security cameras. The museum is, in fact, under video surveillance.