Understanding a usage of ってこと


From the first episode of Death Note:

> フッ… 楽に死なせたり苦しませて死なせたり できるって **こと** か

I know the quoted part (up to and including って) means something like:

> "one can let them die easily or let them suffer and die painfully"

What is the こと doing here? Is it turning it into something like:

> It says, "one can let them die easily or let them suffer and die painfully"?

If that's the case, why isn't こと marked with が or は?

