The investigation into the mid-May murder of a 7-year-old boy in the community of Fujisato, Akita Prefecture, has taken a second bizarre twist since 33-year-old Ms. Suzuka Hatakeyama, who lived two houses away from the boy's home, was arrested June 4 on suspicion of dumping the boy's body by a river, and again June 25 on suspicion of murdering the boy.

On July 18, Ms. Hatakeyama was served a third arrest warrant -- this time on suspicion of murdering her own 9-year-old daughter, Ayaka -- after telling police earlier in the month that she had pushed her from a bridge April 9.

Two factors deserve attention: One is the bizarre nature of the crimes. Why did Ms. Hatakeyama, a divorcee living on welfare, kill her only child and then a neighbor's son within a span of some 40 days? The second factor is the apparently shoddy police work in the initial investigation of Ayaka's death. Police concluded at first that Ayaka had drowned accidentally.