Hamden High School has received an online threat and will be closed Monday and Tuesday while officials investigate, according to Superintendent Jody Ian Goeler.
In a tweet, the superintendent said the school district is working with police and the mayor's office to develop a reopening plan.
Hamden High School will reopen Wednesday with increased safety measures, according to Goeler.
Hamden Police said the threat was made Sunday night and was directed towards the high school community.
"Many students in our community took proactive steps to notify their parents, school officials and police about these online threats," the police department said in a statement.
This comes a couple days after the school district received a different threat and closed school Friday. Police said school officials received a tip around 9:30 p.m. Thursday about an online threat of potential gun violence at Hamden High School and police started investigating.
Officials initially decided to close the school Friday out of an abundance of caution, police said.
Anyone with information is asked to contact Hamden Police at 203-230-4000. Tips can remain confidential.