Five public and charter schools in D.C. received bomb threats on Thursday, forcing staff and students to evacuate. This is the third consecutive day certain D.C. schools received bomb threats, with some experiencing them on back-to-back days, causing mounting disruption.

Impacted students and staff evacuated in accordance with DCPS protocols, says spokesperson Enrique Gutierrez. Tomeika Bowden, chief communications officer for the DC Public Charter School Board, says Cesar Chavez Public Charter School in Mayfair also evacuated due to a bomb threat. Gutierrez says DCPS “takes these threats very seriously” and prioritizes the school community’s safety. “We will continue to work with MPD as they investigate today’s threats,” he says.

The Metropolitan Police Department has not yet determined whether all the threats are related. “These are currently active investigations and there are no additional details available at this time,” says MPD spokesperson Alaina Gertz.

D.C. police are looking into threats made to Cesar Chavez Public Charter School, H.D. Woodson High School in the Northeast Boundary neighborhood, McKinley Tech High School in Eckington, IDEA Public Charter School in Deanwood, and Cardozo Education Campus in Columbia Heights. All the schools have “been cleared with no hazardous material found,” tweeted MPD.

McKinley Tech and IDEA received threats on Wednesday too, along with six other schools across the District. Dunbar High School received threats both Wednesday and Tuesday, when Second Gentleman Doug Emhoff visited to attend a Black History month event.

Police have rendered each campus that’s been threatened so far safe, finding no bombs or hazardous material.

Law enforcement first arrested a 16-year-old boy from Southeast D.C.  in connection to Wednesday’s bomb threats. That suspect is being charged with making terroristic threats. It’s not immediately clear if the 16-year-old will be charged as an adult.

Police announced the arrest of  a second 16-year old boy, this one from Northwest D.C., on Thursday evening. He has been charged with making terroristic threats in connection to the bomb threat at Kipp DC College Preparatory on Wednesday.

Four high schools in Prince George’s County also received threats, WUSA9 reports.

Law enforcement is still investigating whether bomb threats directed at several historically Black colleges and universities in the region are related. MPD Executive Assistant Chief of Police Ashan Benedict said on Tuesday that the Federal Bureau of Investigation is probing a potential connection. Notably, Dunbar High School is the first public high school in the nation to serve Black students. Emhoff had stopped by Dunbar on Tuesday to learn more about the school’s history.

This is also the second day staff and students at H.D. Woodson High School experienced disruptions. Someone fatally shot a woman in the afternoon just a block behind the school. Consequently, they stayed on campus for over an hour past dismissal, according to H.D. Woodson teacher Laura Fuchs. Despite the danger they’ve witnessed, she says students seem “pretty calm.”

“I think that in general our students go through so much that it is almost viewed as normal to them, so very few commented on the events to me, nor acted different,” Fuchs tells DCist/WAMU.

MPD quickly cleared H.D. Woodson, she adds, meaning students and staff were outside for just 30 minutes or so. They returned by lunchtime.

This story has been updated to include information regarding a second suspect being arrested for making terroristic threats.