(CNN) -- A lockdown at an Ohio college was lifted Friday evening, hours after school officials received a "threat of violence," the college's website said.
The alert began around 11:30 a.m. Friday, after a letter sent to a College of Mount St. Joseph administrator threatened violence at the Cincinnati school, according to Delhi Township Police Lt. Darryl Haussler and college spokeswoman Betheny Herr.
"That is when we took action to put the entire campus community into lockdown mode," Herr said.
The school initiated its emergency plan -- including communicating to students, faculty and staff via Twitter, Facebook and text messages. According to a message on the school's website, the order for students, faculty and staff at the college to remain where they were went out at 12:49 p.m.
Hours later, the campus was secured and the college posted on its website that "operations are back to normal."
"Safety is the very first priority," said Herr, adding that there was no evidence of violence or injuries found on the campus.
Campus police will remain present to maintain safety, according to the website.
The Delhi Township Police Department was among the agencies -- along with the Green Township Police Department and Hamilton County Police Association -- working with the College of Mount St. Joseph police to investigate the threat, escort people off campus and secure the campus, Haussler said.
Classes will be back in session Saturday, the school said.
The College of Mount St. Joseph is a Catholic liberal arts institution for 2,400 students -- 1,200 undergraduates and the rest in professional education programs -- located in Cincinnati, in southern Ohio.
CNN's Leigh Remizowski contributed to this report.