division, group, branch

public safety / police officers responsible for matters of national security and counter-intelligence.

Tokyo Metropolitan Police Department Public Security Bureau

day and night

the daytime and the nighttime considered together

guarantee

to reserve, to secure

citizen(s); townsperson/townspeople

to work at a job, to labour / to work properly, to operate, to function; to carry out one's function, to be effective, to come into play / to perpetrate or commit a crime

Alternative spelling of 只働き