If a government worker gets fired for committing a crime, do they lose their pension?

Cop, teacher, fireman, politician, military, civilian who works for the military, regular government worker (employee of a town, city, village, county, state, federal government), is convicted of a crime, do they lose the pension that they paid into?

Is the outcome different depending on the crime?
Is the outcome different depending on the length of their employment?

I had this discussion with several coworkers and nobody knew the answer. I googled it and perhaps because I did not enter the right terms, got all sorts of information, but nothing specific to the answers I was looking for.