You had better hope to God that this is fiction.
Once Lockdown has been achieved, no news comes out which is not pleasant
propaganda, fabricated "feel-good all-is-well" blurbs espoused from the
mouths of cheerful talking-head media figures. But within any area which has
been locked-down, brutal suppression and in fact eradication of all
opposition, real or potential, is the order of the day.
Lockdown can occur practically overnight, with people waking up and, unless
they are very paranoid individuals, not even noticing that while the
uniforms and equipment are the same, their entire police force has been
replaced.
Properly administered, initial lockdown does just this, replaces the systems
which were formerly protective, and carries on as if nothing were changed,
insofar as such a pose does not conflict with the ideological or political
underpinnings which motivate the insurgency. Depending on the degree of
finess of the insurgency, it may be that the only way to tell that one has
been locked-down is by activity which is uncharacteristic of loyalist
systems, such as one's police-force giving aid and comfort to the
invader.