Did Police in Kenya Catch a Serial Killer or Coerce a Confession?

A 26-year-old hair braider named Josephine Owino disappeared one morning last month in the sprawling shantytown of Mukuru Kwa Njenga in Kenya’s capital, Nairobi, after going out suddenly to see someone who had just phoned.

Ms. Owino’s younger sister, Peris Keya, was desperate to find her, and went to three police stations pleading for help. But nothing happened until Ms. Keya said she had a startling dream one night: Her sister appeared, led her up a hill and begged her to search in a pool of water.

Since then, at least 10 sacks with body parts have been fished from an abandoned quarry filled with a thick bed of floating trash, according to the police and human rights activists. The dump was searched only because Ms. Keya, 24, beseeched some local men to help, paying them for the grisly task.

On Monday, the Kenyan police announced that they had arrested a suspected serial killer, who they said had confessed to killing 42 women, including his own wife, in the past two years, and throwing them into the dump.

The suspect’s lawyer accused the police of using torture to extract a confession. And the speed with which the police made the arrest left many Kenyans suspicious. But the police said they had traced their way to the suspect, Collins Jumaisi Khalusha, 33, after doing a forensic analysis of a cellphone belonging to one of the victims.

The discovery of the body parts in the dump — located across the street from a police station — has shocked Kenyans, spreading fear and rumors about who could have committed such grisly murders.