Des Moines, Iowa ? Parents of nine high school students were awakened before dawn by police officers sent to warn them of a suspected suicide pact involving their children, a week after a classmate hanged himself.

Police said details of the suspected plan, including how the students would have committed suicide and whether they planned to do it all at one time or one place, were not known and that the pact may not have been developed that far.

Lincoln High School Principal Al Graziano said a student was overheard talking about suicide Monday night, and later told authorities that others were involved. Officers went to each student’s home early Tuesday.

Many of the five girls and four boys involved were freshmen or sophomores, police said. All were friends of William Metzger Jr., a 15-year-old who hanged himself last week after a car crash that killed three of his friends Sept. 23. The boy’s funeral was Monday.

Klark Jessen, a spokesman for the school system, said several of the students said there was no plan. “Several of them have backed down from their original statements about a suicide pact,” he said.

Five of the students were taken to hospitals “to get some counseling, some help,” said Sgt. Tony Steverson, a police spokesman.

Six of the nine students were back in school Wednesday, Jessen said. Graziano said the parents of two of the students told him Wednesday morning that the students were doing well and could be back in school as early as today.

Lincoln High School, just south of downtown Des Moines, has 2,200 students.

Ellen McGinnis-Smith, Des Moines schools’ deputy director of student and family services, said copycat incidents are a concern after suicide.

“Whenever we do have one suicide, we need to monitor students more closely because history has told us that there can be more suicides,” she said.

Graziano said Lincoln students would be monitored more closely and counselors would remain available as long as needed.

“It’s not every year and it’s not every day that we have four student deaths. For some, it’s their first encounter with death,” he said. “It calls for more sensitivity. It calls for more alertness on our part.”