A Groves High School student is in custody Friday morning after he was accused of sending out a threatening tweet on Twitter, said Groves principal Fred Procter Friday.

In a note sent to parents, Procter said school officials were alerted overnight to "tweets of a threatening nature" generated by one of the school's underclassmen.

The Beverly Hills Police Department was also alerted and able to "very quickly and appropriately" identify the source of the tweets and soon after took them into custody, Procter said.

"I have been in constant contact with the Beverly Hills Police and have been given their assurance that there is no credible threat at Groves," Procter wrote in the Friday email.

"While some chose to re-tweet the message, others chose to contact me and the police, and this is what led to the ability to investigate the situation quickly and effectively," Procter said.

School remains in session Friday for all Birimingham students, including those at Groves. The district's winter break begins Monday.

Procter made sure to emphasize: safety is the top priority for all students at Groves and Birmingham Public Schools.

"As you have read and heard me say numerous times, safety is our top priority," he said.

"Thank you to everyone who helped alert us to the situation and to the Beverly Hills Police who responded quickly and effectively to keep us all safe," he added.

The threat of violence wasn't new Thursday or Friday morning at schools across Metro Detroit. Combined with the week anniversary of the Newtown, CT shootings, as well as threats surrounding the Mayan end-of-the-world prediction, school districts across the state cancelled classses.

Genessee County cancelled classes on Thursday and Friday, as did five school districts in Lapeer County. And on Thursday afternoon, Monroe Public Schools announced they were also cancelling school on Friday. In addition, Lakeland Schools suspended a student Thursday after they reportedly wrote a bomb threat on a bathroom wall.

In the wake of the Newtown shootings, Birmingham Schools Superintendent Daniel Nerad announced late last week that the district would be upping security at all buildings Monday, adding more police presence and filling the hallways with adults.

And on Tuesday, Nerad told the Birmingham Board of Education that the district would be reviewing its safety rules, with a complete report due by the end of January.