"... In the grittier parts of this city, where people inhabit tiny tin shacks and bloated dead animals float along garbage-strewn rivers, police officers are not known as heroes. Instead, many residents see them as a menace, prowling around in dark trench coats with AK-47s slung over their shoulders, extorting money from slum dwellers and killing alleged suspects — and sometimes not even suspects but simply poor people they come across. "They kill for free,' said one young man in the Mukuru Kayaba slum, where Mr. Muthini was shot. ..."