Police and school officials are responding to rumours of an online suicide pact among students at a Barrie, Ont. high school.

As many as 17 students at St. Joan of Arc High School are rumoured to be involved in the pact. And the schoolyard chatter is being backed up by tragic incidents such as the suicide of a 14-year-old girl on April 9 and another suicide by a 16-year-old girl two weeks later.

There have also been two suicide attempts at the Mapleton Avenue school in the past month.

The incidents have parents and teachers talking. The latest in a long string of letters from Principal Darren Schmidt tried to reassure parents that the school is treating the rumours seriously.

"We want to reassure all families that when rumours of a suicide pact surfaced quite some time ago, they were taken very seriously and fully investigated at the school and by Barrie Police Service," Schmidt wrote.

"All investigations have shown these rumours to be unsubstantiated and police are treating these deaths as unrelated incidents."

But parents are not convinced and they allege the pact surfaced on the increasingly popular social networking website Facebook.com.

Michael O'Keefe of the Simcoe Muskoka Catholic District School Board said rumours of the pact continue to cause concern.

"The follow-up from this has continued to cause a considerable amount of grief in the community (and) a considerable amount of concern as we are all very much concerned about the health and welfare of all of our students," O'Keefe said.

Since the deaths, students have posted condolence messages on the Facebook pages.

Barrie police officers say they have interviewed dozens of students and scoured the website for clues but have found nothing to indicate the existence of a suicide pact.

But students say the original posting has been removed from Facebook, which they claim called for one student to commit suicide every two weeks.

They also say that 17 students signed on.

A student named Erin told CTV's Austin Delaney that she was apparently on the list but did not know anything about it.

"Apparently, I'm supposed to die tonight ... It's just ridiculous."

Police have spoken with her and many others. Most of the students they have spoken with have never seen the list.

Even when officers approached people who were rumoured to be on the list, those students said they had never seen the posting either.

"We don't have a list," police Sgt. Dave Goodbrand said. "We hear it, we go see a youth that ... we hear ... has seen the list (but) you go talk to that student and it's like, 'I didn't really see it but a friend of mine saw the list.'"

Investigators are continuing to look into the rumours. But most students do not believe a suicide pact actually exists.

With reports from Austin Delaney and Janice Golding