If the burned-out cars, bullet-riddled schools, demolished buildings and desolate streets in downtown Port-au-Prince weren’t enough evidence of the terrible things that happened here, someone left an even more ominous hint: skulls in the middle of the street.

A human head propped up on a stick with another on the ground beside it in front of a government office was apparently intended as a menacing message from gang members to the Kenyan and Haitian police officers trying to restore order to Haiti: Beware, we rule these streets.

A Kenyan police officer wearing a bulletproof vest and helmet and patrolling in an American armored personnel carrier took a photograph with his cellphone, while another maneuvered the vehicle around the skulls.

I, along with a New York Times photographer, went on patrol through Port-au-Prince, Haiti’s capital, with a Kenyan-led multinational security mission deployed in the country. During the six-hour tour, the Kenyans were mostly ignored by people on the street and occasionally heckled; the vehicle was shot at once.

The patrol offered a glimpse into the enormous challenges the Kenyan force faces in trying to wrest control of Port-au-Prince from armed groups that have unraveled life in the country, killing indiscriminately, raping women, burning neighborhoods and leaving hundreds of thousands hungry and in makeshift shelters.