Threats to schools in the area around Oakland County were not credible, sheriff Mike Bouchard has said, as dozens of schools in southeastern Michigan remain closed for another day.

“If you’re making threats, we’re going to find you,” Mr Bouchard said threats that were reportedly circulating online. “It is ridiculous you’re inflaming the fears of parents, teachers in the community in the midst of a real tragedy.”

On Thursday, a teenager was arrested not far away from Oxford. in Flint, for making a false threat in a video recorded on a school bus, as The Associated Press reported.

The Oakland County sheriff has appeared to criticise Oxford High School for not alerting him to what was allegedly unfolding in the classroom ahead of Tuesday’s fatal shooting.

Mike Bouchard, the sheriff, said on Thursday that “In light of where we are today, certainly we would have liked to have been part of that discussion and information.”

His remarks were an apparent reference to a meeting between Oxford High School and the accused’s parents, which was confirmed by Tim Throne, the school’s superintendent on Thursday.

Mr Throne said “discipline not warranted”.

Two teachers meanwhile told CNN that they alerted the school to both “concerning” and “disturbing” behaviour exhibited by the 15-year-old, Ethan Crumbley, in the 48 hours before the attack.

He allegedly received counselling the day before the shooting.

The superintendent of Michigan’s Oxford Community Schools has said the 15-year-old suspect in Tuesday’s mass shooting was not disciplined during a meeting in the school’s office earlier on the day of the killings.

“To say that I am still in shock and numb is probably an understatement. These events that have occurred will not define us,” a stoney-faced Mr Throne said.

The Independent’s Shweta Sharma has more details.

Revelations about suspect Ethan Crumbley’s menacing social media posts, confessional videos and ‘disturbing’ classroom behaviour have sparked a debate over whether more could have been done to prevent the deadly shooting at Oxford High School.

The Independent’s Megan Sheets has more details.

In his first remarks following the tragedy, school superintendent Tim Throne has said that it was decided “no discipline was warranted” during a behavioural meeting with the suspect just hours before the shooting.

“To say that I am still in shock and numb is probably an understatement. These events that have occurred will not define us,” Mr Throne, leader of Oxford Community Schools, said in his first extended remarks since the incident.

His remarks came in a 12-minute video as he spoke slowly with a grim expression.

“I want you to know that there’s been a lot of talk about the student who was apprehended, that he was called up to the office and all that kind of stuff. No discipline was warranted,” Mr Throne said.

“There are no discipline records at the high school. Yes this student did have contact with our front office, and, yes, his parents were on campus [on] 30 November.”

Mr Throne lamented that Oxford High School looks like a “war zone” and won’t be ready for weeks. But he repeatedly lauded the students and staff for how they responded to the violence at the time of shooting.

“I want you to be as proud of your sons and daughters as I am,” Mr Throne said, adding that he also urged the sheriff’s office to publicly release the video of the students from Tuesday.

Mr Throne said he couldn’t immediately release additional details as sheriff Mike Bouchard has said Crumbley’s classroom behaviour on the day of the shooting was a matter for the investigation.

About 60 schools in Michigan have been temporarily closed following copycat threats following the Oxford school shooting, Oakland County Sheriff Michael Bouchard said, reported Newsweek.

Mr Bouchard said there were at least 100 instances of threats either direct or on social media across the state.
But investigators believe that they were false copycat threats, as several students might have been doing it for fun or to get class cancelled.

“It is not [funny],” Mr Bouchard said. “It is a crime, and if you’re making threats, we will find you.”

“It is ridiculous you’re inflaming the fears of parents, teachers in the community in the midst of a real tragedy,” he added.

The sheriff complained that the false threats are “overrunning our resources” and stretching the local law enforcement thin.

Prosecutors have suggested that the parents of the Oxford High School shooting suspect Ethan Crumbley, 15, could themselves be charged after the incident that left four students dead.

Experts say it is rare for parents to be charged in the US over school shootings involving their children, even in cases where a minor used their parents’ or relatives’ guns.

William Swor, a defence lawyer who is not involved in the case, told the Associated Press that charging the parents would require a “very fact-intensive investigation”.

“What did they know and when did they know it?” Mr Swor said. “What advance information did they have about all these things? Did they know anything about his attitude, things of that nature. You’re talking about a very heavy burden to bring on the parents.”

The child access prevention laws related to guns vary widely across US states and only just over half of them have such laws.

Gun control advocates say the laws are often not enforced and the penalties are weak.

“Our laws haven’t really adapted to the reality of school shootings and the closest we have are these child access prevention laws,” said Kris Brown, president of the Brady gun control advocacy group.

Ann Arbor has become the latest Michigan city to close public schools due to threats, with officials saying on Thursday night that all school buildings would be shut down.

“While these posts have not been determined to be credible at this time, the volume is quite high,” wrote city superintendent Jeanice Swift in an email to teachers and parents seen by All About Ann Arbor.

“Closing schools will allow school administrators and law enforcement an opportunity to investigate all reported concerns. It will also allow us to reset our learning environments that were significantly impacted today by rumors and concerns stemming from social media chatter.”

She added that the FBI and the Michigan State Police are monitoring threats on social media, and asked parents to explain to their children how severely such threats are treated.

“Law enforcement and school leaders will investigate every threat and take whatever action is warranted to protect our students and community, up to and including prosecution for those responsible,” she wrote.

As charges against the parents are expected to be announced on Friday, the prosecutor has repeated her criticism of the parents of the suspect, Ethan Crumbley, in the Michigan school shooting.

Oakland County prosecutor Karen McDonald told WJR-AM the parents’ actions went “far beyond negligence”.

“The parents were the only individuals in the position to know the access to weapons,” Ms McDonald said. The gun “seems to have been just freely available to that individual”.

The semi-automatic gun which was used for the shooting in the school was purchased legally by Mr Crumbley’s father last week, according to investigators.

Why have Michigan prosecutors taken the unusual step of charging Ethan Crumbley with terrorism?

But, she said, the intent was to address how the shooting impacted people throughout the community who were not killed or injured, in the form of fear and trauma.

“What about all the children who ran, screaming, hiding under desks?” Ms McDonald said. “What about all the children at home right now who can’t eat and can’t sleep and can’t imagine a world where they could ever set foot back in that school?

“Those are victims, too, and so are their families, and so is the community. And the charge of terrorism reflects that.”

Oakland County Sheriff Mike Bouchard said he “100 per cent” agrees with the charge, saying: “If you weren’t hit by a bullet, it doesn’t mean you weren’t terrorized that day and won’t have nightmares about (it) the rest of your life – whether you’re a parent, a teacher or a student in that class.”

The ability to levy such a charge is borne from Michigan’s controversial 2002 anti-terror act, passed in the aftermath of 9/11. Whereas most definitions of terrorism require some kind of political goal, Michigan’s defines it as a violent felony act “intended to intimidate or coerce” a civilian population or a government.

At the time, the American Civil Liberties Union urged Michigan’s legislature to limit the scope to “violent actions like those that occurred on September 11”.

Former federal prosecutor Matthew Schneider told the Associated Press: “This is why we have this law. It’s for this type of case. This is not just a murder case. It’s going to terrorize a generation of these kids who were in the school. The impact is on thousands of people.”

Mr Crumbley has pled not guilty to all charges.