RAMBOUILLET, France—French prosecutors opened a terrorism investigation into the fatal stabbing Friday of a French police official inside a police station near the historic Rambouillet chateau outside Paris. Police shot and killed the attacker at the scene, authorities said. Anti-terrorism prosecutor Jean-Francois Ricard told reporters that his office took over the probe because the attacker had staked out the station, because of statements he made during the attack, and because he targeted a police official. Ricard did not provide details on the attacker’s identity or motive. French media reports identified him as a 37-year-old French resident with no criminal record or record of radicalization. A French judicial official said the suspect was born in Tunisia and that witnesses heard him say “Allahu akbar,” Arabic for “God is great,” during the attack. The judicial official was not authorized to be publicly named speaking about an ongoing investigation. French Prime Minister Jean …