Double jeopardy

I’m no lawyer, but I am just wondering what legal remedies are open to cases where new evidence has been discovered, but a person cannot be tried because of double jeopardy.

I can understand that the law should offer equal protection to all, but obviously there is a substantial gray area that exists. 

As far as I am concerned, when guilty persons are able to escape sentence because of a technicality then there is a failure of justice. In such cases, moves should be made to change the law to prevent the guilty from going free.

Some may argue that one cannot presume guilt, but when the process of going beyond a presumption, is stopped by the law itself, then it becomes a complicated moral process which sometimes results in derailment of justice.

One phrase that comes to mind to is this:

“Justice delayed is justice denied”,  my corollary to this is “ Justice denied is judicial injustice”