I don't know what you're trying to say with that but.

The detective Arthur Brand made this possible, the English Wikipedia is not as thorough as I'd like but he's an almost later then life character.

He has ties within the organized crime world, where these paintings are almost always used as deal sweeteners, to bargain for less time behind bars or as escrow material for large deals.

Because some of those paintings are too high profile they'll lose their useage. In this case the person holding the item wanted to return it without anything in return (as it basically lost is worth in criminal circles). He returned it to Brand in aan ikea bag.

The police were involved, but in the sideline. Brand has his reputation to manage and always informs police, but only so they don't interfere. If the person doing the handover was to be arrested, no one would ever come forward again with art treasure like this.

There's a documentary series on Brand and it's incredibly intriguing how he goes after stolen art. He managed to get a long lost Picasso back, that was left for him on a dark car park in the middle of the night.

Seriously you would imagine most of the stuff that he does make up or being fictional, but it's his real life work.