DNA tests prove a baby boy found dumped in Roermond in June has an older sister, the public prosecution department said on Friday.

The girl was also a foundling. She was left in a car park in Hürth near Cologne in Germany in October 2011, around 100 km from Roermond.

Social services are now investigating whether the boy can be placed with the same family as his sister. Both children have the same mother but further tests are needed to find out if they have the same father, the department said.

Both children were found wrapped in a blanket, close to a road. Their umbilical cords had been clamped.

One child a year

Statistically, one child a year in the Netherlands is abandoned in a public place, according to the child protection council.

In eight of the 12 cases since 2003, the mother has been indentified.

Abandoning a child is punishable by a 4.5 year jail term or a fine of almost €20,000, although prosecutions are very rare.