Washington College in Chestertown, Md., shut down Monday because of a warning about a student armed with a gun.

Police are treating the student as a missing person, and there’s no indication that he has done anything wrong, but the lockdown was extended overnight Monday as police continued to search for the missing student.

College officials announced Monday evening that they planned to reopen the college Tuesday morning with a continued police presence on campus.

Many students expressed concern about returning to classes, but the college posted a message that there had been no direct threat to campus or anyone at the college and after close consultation with law enforcement they had determined that it would be safe to resume normal operations Tuesday. Attendance was not mandatory: “We’ve asked faculty to be flexible regarding class attendance and not penalize students for their absence. Students who wish to remain in their residence halls tomorrow should feel free to do so.”

Counseling would be available Tuesday, the announcement added.

The alert began early, with a pre-dawn warning.

“College closed. Shelter in place,” was posted on the Web site of the small liberal arts college on the Eastern Shore all day.

Shortly after 7:30 a.m., the college posted on its Web site:

We received notification early this morning from the parents of sophomore Jacob Marberger that he had returned home and retrieved a firearm. The parents have not been able to reach him and do not know where he is or where is he is headed.
Due to an abundance of caution the college has decided to close campus for the time being and asks all students and staff on campus to shelter in place. Anyone off campus should stay away from campus until further notice.
Public Safety has requested and received support from local law enforcement who are now on campus. A sweep of the parking lots and campus buildings is being conducted.

“You could call it an overabundance of caution — the way everyone on campus is sheltering in place,” said college spokesman Michael O’Connor. “[For] everyone not on campus, we would like them to stay away.”

Shortly before 9 a.m. Monday, the college posted an update that the student is believed to be still in Pennsylvania, but they continued to ask students and staff on campus to shelter in place, those off campus to avoid the area, and anyone who has contact with the student to call campus police.

Marberger, who is from Pennsylvania, is a leader in student government and fraternity brother at the college.

The student government association president did not respond to a request for comment Monday.

On Monday morning the Elm, the student newspaper on campus, reported that concerns began with postings on social media overnight.

Shortly before 10 a.m. the college added an update from the Chestertown Police Department that the student is considered a missing person. He is not accused of any wrongdoing. Marberger is described as 5 foot 4 inches tall, 130 pounds, with light skin and curly brown hair and was last seen driving a 1997 dark green Land Rover with Pennsylvania license plate beginning with “JWY.”

Residents of the Cecil, Dorchester and Talbot dorms are being moved from their dorms at the request of law enforcement to help their search of the buildings, to the Hodson Hall Commons.

The Chestertown Police Department is being assisted on campus by the Kent County Sheriff’s Department, Maryland State Police and the campus public safety department.

Shortly before 11 a.m., as police continued their investigation on campus, students were allowed to leave their rooms to use bathrooms but were advised not to leave the building.

In the student’s home town, his former high school went under a precautionary lockout procedure, allowing people to enter and exit the building with supervision. Other schools in the district would hold recess indoors Monday. District activities were canceled for the afternoon and evening. The school posted this public alert on its Web site:

“Students and staff are safe, with normal operations going on inside of the building. District representatives just learned that Washington College, in Maryland, instituted a lockdown due to a threat to their campus made by a person who is a former Cheltenham student. We have been notified that this individual is not presently in our area. We are utilizing an abundance of caution, nonetheless.”

His father declined to comment Monday morning.

This post has been updated.

Staff researcher Jennifer Jenkins contributed to this report.