Victims died in their cars from carbon-monoxide poisoning.
Nine young people committed suicide in two separate incidents on Tuesday by burning traditional rentan charcoal stoves in sealed-up cars, police said.
They all apparently died of carbon-monoxide poisoning, police said.
Four men and three women in their teens and 20s were found dead in a car in Saitama Prefecture. The bodies of two women in their 20s were discovered in a car in Kanagawa Prefecture.
Police suspect both suicide pacts were initiated via the Internet.
The police were tipped off to the deaths in Saitama by a caller living in Sapporo. The man, 21, was acquainted with one of the victims.
He called the Chichibu Police Station in western Saitama Prefecture at 5:50 p.m. on Monday to relay a phone text message he had received from his friend.
It said: ``I am now in Minano town (next to Chichibu). There are seven people in our car. We are going to commit suicide.''
Officers from the Chichibu Police Station started searching Minano town, which is in its jurisdiction, and found the victims' station wagon at 6 a.m. Tuesday in a parking lot at Minoyama Park.
The occupants of the car were already dead. A woman was in the driver's seat; two women and a man were in the second-row seat, and three men were in the third-row seat. Police are now investigating the identities of the seven people.
There were four rentan charcoal stoves in the car, and the car windows were sealed with tape. The rented car had a license plate from Shinagawa, Tokyo.
Just minutes later at 6:15 a.m. in Kanagawa Prefecture, police found the two dead women near a shrine in Yokosuka. In the car, there were two rentan charcoal stoves and two letters addressed to family members.
One of the women is thought to have been 27 and from Yokosuka; the other is believed to have been 21 and from Tokyo's Setagaya Ward. Police suspect they also became acquainted with each other through a Web site.
Last year, 34 people who apparently met through the Internet died in 12 group suicides throughout Japan, according to the National Police Agency.
In the first six months of this year, 11 people have died in five group suicides, the NPA said.
Another group suicide recently occurred in Minano on Sept. 28, when four people died. Police suspect those four also became acquainted through Web sites.(IHT/Asahi: October 13,2004)