I reckon if a cat wants to leave he/she will leave if they really want to to get back to their owners. I guess ashwin preferd you. And i guess the original owners didnt look after him well thats probably why ashwin left to find a better place with you.
MC my 19 year old cat showed up one day and never left our house perimiter for 19 years was 100 percent free to roam, but she never left at all.