Four more people have been taken into custody in connection with last month’s high-profile jewel robbery at the Louvre Museum, the Paris prosecutor’s office said Tuesday.

Prosecutor Laure Beccuau announced that two men and two women, all residents of the greater Paris area and aged between 31 and 40, were arrested as part of the widening investigation. Authorities did not disclose the specific roles the four are believed to have played in the Oct. 19 theft. Under French law, they may be held for up to 96 hours of questioning.

None of the stolen items — valued at roughly $102 million — has yet been recovered. The missing collection includes a diamond-and-emerald necklace gifted by Napoleon to Empress Marie-Louise, pieces linked to Queens Marie-Amélie and Hortense, and a pearl-and-diamond tiara worn by Empress Eugénie.

Earlier arrests targeted other suspected members of the team believed to have executed the rapid daytime break-in. Investigating judges previously filed preliminary charges of robbery and criminal conspiracy against three men and a woman detained in October.

The audacious theft has renewed scrutiny of security measures at the Louvre, the world’s most visited museum. The robbers took less than eight minutes to enter through a window into the Apollo Gallery, smash open display cases with power tools, and flee with the jewels via a freight elevator, where scooter riders were waiting.

Empress Eugénie’s emerald-studded imperial crown featuring over 1,300 diamonds— was later found abandoned outside the museum.