After hearing that, it seems more and more peculiar that nobody thought to check inside or realized anything was wrong.
この場合、次のような言い方ができますよ。
ーAfter hearing that, it seems more and more peculiar that nobody thought to check inside or realized anything was wrong.
「それを聞くと、誰も中を確認しようとしなかったり、異変に気が付かなかったのが、ますます不思議だよね」
peculiar「奇妙な・おかしな」
ご参考まで!