"The chances of this exact event are 1 in a trillion, therefore with a high degree of confidence, it isn't happening and I am in fact hallucinating. You're not real, Bob from highschool!"
And imagine how often you almost run into acquaintances on the street, and don't notice. It must happen more often than when you do notice. If you made a concerted effort to look for near-coincidences, you would suddenly find yourself noticing lots more unlikely things that were happening all along.
Once you start digging into someone's life you'll learn all sorts of things that might seem really unlikely... but you'd find unlikely things in someone's life picked at random, you just never dug into them, because they're not accused of murder.
And imagine how often you almost run into acquaintances on the street, and don't notice. It must happen more often than when you do notice. If you made a concerted effort to look for near-coincidences, you would suddenly find yourself noticing lots more unlikely things that were happening all along.
Once you start digging into someone's life you'll learn all sorts of things that might seem really unlikely... but you'd find unlikely things in someone's life picked at random, you just never dug into them, because they're not accused of murder.