https://www.theguardian.com/world/2021/jun/21/italy-recovers-nearly-800-illegally-gathered-archaeological-finds
talk about jigsaw puzzles......what a lightbulb moment
The Italian carabinieri are absolutely superb at this stuff - when British forces were trying to help the Iraqis with cultural protection in the south of the country post the 2003 invasion, the British-led division included some carabinieri who were there to train the Iraqi police, and they called in their mates on the cultural protection side of the house. The world leaders amongst police forces for this work.
A couple of years ago in one of Rome's many museums, I came across a gallery dedicated to detection of stolen and fraudulent sculptures. The latter often took parts of one or more genuine statues and then added limbs, heads, or other parts either from more modern pieces or manufactured to suit. It was really quite an interesting display.