Anyone seen the cat?

Hello Last night there was a strange incident, which made me turn to you. I was still awake when my mother came into my room with a frightened look on his face. She told us that our cat Asya (who sleeps with his mother on the bed), when she was almost asleep, suddenly jumped up and rushed to her feet. Began to growl and look in the window.
I reassured her, she said that cats sometimes act. She went back to sleep. But after a while I heard a knock on the wall, it knocked my mother. When I went into her room, she told me that cat again behaved like that. only growled louder. We greatly frightened. Inspected the room, but no one and nothing. Mom had to sleep in the room with light. But under the morning she left the room. The cat was jumping again, but this time without the roar.

In the house since it was built, no one died. What could it be?

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