Hours after a campus lockdown, police started a “slow, methodical removal” of staff and students who were ordered to take shelter in campus buildings, Lt. Larry Klaus said.

In a tweet earlier, the city said: “The suspect is a 19-year-old black male who is approx. 5 foot 9 inches tall. He is wearing mustard yellow jeans and a blue hoodie. He may have taken off the blue hoodie.

“He is considered armed & dangerous. If you see the suspect, do not approach him. Call 911.”

The shooting occurred around 8.30am at Campbell Hall, a residence hall at Central Michigan, which is about 70 miles (112.6 kilometres) north of Lansing.

Klaus described the shooting as a “family-type domestic situation” and said the victims were not students.

Klaus said video at the dorm suggests Davis fled on foot after the shooting. He was wearing a hoodie but had been shedding certain clothes while on the run.

“This has been a tragic day. ... The hurting will go on for a while,” said university President George Ross.

The search was focused on Mount Pleasant neighborhoods near campus. Officers in camouflage knocked on doors and checked possible hiding places, such as yards and porches.

In the surrounding community, students and staff in the Mount Pleasant school district were told not to leave nine buildings.

Klaus said Davis was taken to a hospital Thursday night by campus police because of a drug-related health problem, possibly an overdose.

Davis is from Plainfield, Illinois, and graduated from Central High School in 2016, said Tom Hernandez, a spokesman for Plainfield School District 202.

The shooting occurred on the last day of classes before a weeklong break. Parents who were trying to pick up students were told instead to go to a local hotel where staff would assist them while the manhunt was ongoing.

“The university is taking all precautions. The number one priority right now is safety,” said university spokeswoman Sherry Knight.

A student, Tyler Whipple, was driving through campus when his route was blocked off by police cars at the scene of the killings. He had to catch a flight to Florida.

“These roads are kind of spooky right now,” Whipple said.

The school posted an alert Friday morning on social media about shots being fired at Campbell Hall. An automated phone message also was sent to students.

Halie Byron, 20, said she locked herself in her off-campus house, about a 10-minute walk from the dorm. She had planned to run errands before traveling home to the Detroit area.

“It’s scary thinking about how easy a shooter can come into a college campus anywhere - a classroom, a library. There’s so much easy access,” Byron said.

A Twitter user, whose handle is simply “V”, wrote just after the shooting: “This is surreal. I shouldn’t be in a dark locked room hiding right now. I never thought this would be me going through this. 

“I just wish our country wasn’t this way.”

The shooting comes amid a renewed debate over pervasive gun violence and law enforcement’s role in stopping potential shooters, which was sparked when a teenage gunman killed 17 people at a Florida high school two weeks ago.

The gunman in that shooting had a history of run-ins with law enforcement, which have faced scrutiny over their failure to intervene despite multiple warnings.

It was unclear what kind of weapon the shooter in Michigan used or how he acquired it.

The state of Michigan allows for the concealed carrying of a handgun with a permit, but Central Michigan University does not allow guns on campus.