The suicides earlier this week of nine people have renewed concerns over the suicide-related Web sites through which they are believed to have met.

The controversial Japanese Web sites put suicidal people in touch with others who want to kill themselves, but don't want to do it alone.

On Tuesday, seven people were found dead in a car in Saitama Prefecture at around the same time as two others were found, also in a car, in Yokosuka, Kanagawa Prefecture. All nine died of carbon monoxide poisoning after lighting charcoal burners inside the sealed vehicles.