This is a true ghost experience a friend on mine had in his parent's house in Mexico City some years ago.
I was not sure whether to submit this story since most of the stories I have read here are written by people who directly witnessed the experience they are describing. However, the story I am just about to tell you is quite interesting to keep it covered just because it did not happened to me.
About ten years ago my friend was living with his family in an spacious two-level house in Mexico city. Then they had a maid who had been living with them for a while. She was a young single mother of a baby girl. At night mother and daughter slept together in a room located on the first level. The baby used to spend the day in a cradle while her mother was undertaking her domestic duties. Everything was fine until one day a tragedy occurred.
Unfortunately the cradle was dangerously close to a window. Somehow the baby got the cord of a curtain around her neck and hanged herself. Nobody in the house could hear anything. Of course the mother was devastated to see her baby girl die in such an tragic way. After the funeral she decided to leave the house for her own sake.
Some time later my friend's mother hired a young couple with no children to take over the position that the maid had left vacant. She allocated them in the same room where the tragedy occurred without saying a word about what had happened there. But the couple had not spent two weeks in the house when they decided to leave what they called a "haunted house".
They argued that every night since they moved into the house they heard a baby crying. The first night they thought there was a baby in the house, so they weren't concerned too much about the whimpering. However, they were terrified when they learned that a baby died in such room and noticed that every night, about the same time, the phenomena took place again.
My friend and his family were confused. They are not the sort of people who believe in ghosts. In any case, they asked a priest to come to their house to bless the room in which the baby died. The priest did as requested but the whimpering remained. It seemed as something else had to be done.
After several days of enduring the situation, my friend's parents finally decided to asked the baby's mother to visit the house again. She brought with her a sort of medicine-woman to "clean" the room. Amazingly, after this visit, the whimpering stopped permanently.
Was the work of the medicine-woman or the baby's mother's visit what solved the puzzled? Probably nobody will ever know, but I like to think that the baby girl needed to say a last good bye to her mother.