Victoria

Arlo was between three and five,strictly indoors, perfect health as far as I know, he was normal when I left playing with his brothers and when I came home from work about twelve hours later he had passed away. He was in the window ( which is a considerable jump they make often ) and his eyes and mouth where closed. The only sign of anything was some foam coming out of his mouth and nose but mainly nose. I have not been able to stop crying or blaming myself because he had to have gotten into something right ? My other two cats and dog are fine and trust me they would have all gotten into it together, and he jumped in the window if he was in danger I don’t think he could do it, also if something was ingested would it even kill him so quickly? If anyone has any alternative scenarios backed with facts or experience please let me know I just want to know what could have caused this.