This happened to my uncle's family a year ago. My uncle was a businessman (now he had left his job) and he had all sorts of relations with people. Some were his true friends while some others were the untrustworthy ones. He had a son and a daughter who was blind and deaf by birth. She had never seen her own parents or ever heard their voices, yet she was adored by everyone in the family.
There was a guy, named Shivraj - one of my uncle's true friends. My uncle thought that he was so faithful that he could never cheat on him. But it was one of the biggest mistakes that my uncle thought of him like that (He was worldly-minded and the aim of his life was just money, money and money. My uncle realized this when he lost his son because of his greed for money). The story was something like this...
One day my cousin, i.e. My uncle's son, was playing outside. Just then Shivraj saw him (I'm not sure what really had happened. It's just a guess). My cousin was kidnapped for ransom. Mr. Shivraj was the culprit. He was behind the property that my uncle was owning.
We all were shattered when after 2 or 3 days, we came across the news that my cousin was no more. He was murdered and the murderer was Shivraj (God knows why he did that). My uncle-aunt were broken. But they were unaware about the deceitful plans of brutal Shivraj.
A month passed. The matter was settled. Uncle-aunt somehow managed to cope up with the loss. Everything was fine. But then, strange things began to happen We noticed that their daughter began to smile at herself. She clapped as if she was seeing something. She showed very strange behavior. One day, my aunt even caught her holding a pencil in her hands and writing something. She was amazed. We also heard her saying "Mummy-Daddy" very often which she had never heard before. Uncle thought that she was recovering her weaknesses but she was seeing the spirit of her brother - that's what my grand mom said.
The most freaky incident took place when my uncle was going to sign a deal with Shivraj. It happened when his daughter came to knew that her dad was signing a deal with Shivraj. She just cried aloud and started shouting. All were confused. Just then she took a marker out of the cupboard and wrote on the wall, "Don't go father... He will murder you just what he did to me". Out of horror and bewilderment, he didn't go. He was saved by his daughter rather his son (that's what I feel).
Today also, we all believe that his soul lives in their house and protects everyone from difficulties.