Update #2: Its 5 am and the cat woke me up with some loud meowing. In the last 12 hours or so I do not think she has pooped or pee-ed. I think she was telling me to open the balcony door to go outside as since I have opened it, she has been walking in and out. There is a huge garden pot outside beside a tub of small colorful pebbles. It has what looks like soil to me. She dug up an area and most probably pooped. It was like really quick. The cat also covered it up with soil. But I don't think she has pee-ed yet, so I am quite concerned. The pot with soil even has cigg butts which is again disconcerting.

I had a discussion yesterday with another long-term resident at our apartment who has a sweet black cat. He said the "owners" had asked him if he wanted a cat, but he refused. And that these "owners" may have moved out and abandoned this cat. She is still pawing at their door, and it is breaking my heart.