The general public have a warped view of the speed at which an investigation proceeds. They like to imagine tense conversations going on behind the venetian blinds and unshaven, but ruggedly handsome, detectives working themselves with single-minded devotion into the bottle and marital breakdown. The truth is that at the end of the day, unless you've generated some sort of lead, you go home and get on with the important things in life - like drinking and sleeping, and if you're lucky, a relationship with the gender and sexual orientation of your choice.
Ben Aaronovitch (2011). “Moon Over Soho”, p.33, Del Rey