I think I saw a ghost?

Okay so the other night I was home alone and I walked into my kitchen - it was pitch black, no lights on, the blinds were closed and there were no appliances on or anything like that. I was about to turn on the light when I saw these two bits of white light. I can't really describe it, they were basically just thick lines. They were moving in unison and they kind of swished to the left and then they disappeared. They were only there for about 3 seconds. My great aunt died a few weeks ago and I'm wondering if it was her?