MADRID - A Madrid court on Thursday shelved a five-year-old investigation into the raid of the Gaza-bound Mavi Marmara flotilla, though the probe could potentially be re-opened if Prime Minister Benjamin Netanyahu ever visits Spain.The 2010 raid killed nine Turkish activists, while a tenth Turk died four years later from his injuries. Spanish activists were also on board the ships.Spain has pioneered the use of universal jurisdiction, the concept that alleged crimes against humanity can be prosecuted across borders. The law was recently changed, however, so that judges could only investigate such cases if there was a Spanish connection, such as a native victim or perpetrator. The Madrid court said in a written ruling on Thursday that it was closing the case in which Netanyahu and several of his ministers were accused of crimes against humanity.But it left the possibility that the case could be re-opened, saying the investigation was shut until Netanyahu and those targeted by it came to Spain. It did not make clear what steps would be taken if they did.