After My Best Friend Died, She Was Still Sending Me Messages

My best friend fell to her death from a building. The police concluded that she committed suicide. Everyone told me to put it down as soon as possible. But starting from the night she was buried, messages from her popped up on my phone every night. She chatted with me about daily life, talked about what was on her mind, and even accurately described every move I made when I was alone. She understood me better than she did when I was alive. I was deeply afraid, thinking that my best friend was obsessed with me and haunted by ghosts. But as I dug deeper and followed the clues, it became more and more creepy - these strange messages were not the work of the undead at all, but a carefully planned fatal scam. The relatives and friends around me had abnormal expressions and unified words. Shrouded in layers of fog, I finally discovered that my best friend's death was never an accident, and the mysterious person who continued to send me messages was just to cover up the truth and drag me into the abyss.