More than 23 years after they were snatched from a New York gallery, four valuable paintings have turned up in the western German city of Cologne, police said Friday.

The works valued at $345,000 (258,000 euros) when they were stolen in July 1988 surfaced in a collection bequeathed to a woman in Germany in 2009, the Cologne police said in a statement.

"The heiress wanted to research their origin and authenticity and turned to the Art Loss Register in London and the Cologne police," it said.

The Art Loss Register, which calls itself the world's largest database of stolen art, determined that the four works were among those taken by burglars from New York's Salomon gallery.

It was not immediately clear how they ended up in Germany, police said, adding that the US Federal Bureau of Investigations had been involved in the probe.

The paintings that resurfaced included "Figuration" by Robert Motherwell, "La Bouteille bleue" by Fernand Leger, "Untitled" by Franz Kline and Jean Dubuffet's "Effigie".

The works have now been handed over to an insurance company.