We can assume the 'time-police' were started by a Vulcan, not to mention the actual 'time travel' and/or 'time-line differential detection' technology. So when Vulcan blew-up the 'time-police' ceased to exist.

Imagine time-line
a->b->c->d->e ... -> t

a: vulcan teaching creating core understanding of time travel
b: Captian Archer
c: Captian Kirk
d: ( Read more... )