We can't quite put our finger on it ... but there was something strange about our encounter with "Blade Runner" Oscar Pistorius in Los Angeles back in October ... something ... creepy.
On the surface, he was totally polite with our camera guy as he left dinner at Mercato di Vetro with a friend ... answering questions about his running style.
Notably NOT present during the run-in -- Reeva Steenkamp ... who was gunned down in Oscar's South Africa home early Thursday morning. It's unclear if they were dating at the time.
Oscar is the only suspect in her death.