Baby lifted by ghost- Scary Experience

So this isn't a story of mine personally. I've never really had my own encounter with the supernatural, and honestly, I'm not sure if I should be disappointed or not. No, this story actually includes my Girlfriend.

When she was about 10 or 11 years old, she and her family (Dad, Step mom, Step Sister) moved into an old Town House. After living there for about a year, weird things started happening. Tamara's (my girlfriend) step mom had just given birth to her new sister about 2 months prior.

female ghost picture
Female ghost captured by a camera in united states
Her step mom would put Tamara's sister in her crib for naps. The first time this ever happened, everyone heard noises coming from her room, so thinking that the baby was awake, and my girlfriend's step mom went to grab her. She wasn't in her crib.

Instead, the baby had somehow found her way onto her Mother's bed, sound asleep. Now remember, she was 2 months old, not even able to stand yet. This happened multiple times, for a month straight, before finally stopping. This isn't the only thing they experienced in the house.

Tamara claims to have been pushed down the stairs three times while living there, and claims to have seen someone walk past her bedroom, and when she would ask if anyone had walked past her room that night, she was always told no.

Just a little curious to what could have been in that townhouse? I've never heard of a spirit able to lift a baby before. It never hurt the children, only my girlfriend, and only by pushing her down the stairs. Very curious, very interested. Any input would be awesome.