Five hours after initial reports of a gunman being on Yale University's campus, law enforcement are still searching for the person in question, but with new details.

New Haven Police Department spokesman David Hartman said in a press conference the anonymous called still has not been identified, but it is something law enforcement is working on. He also said the caller made the tip, was asked to stay on the line, but did not and hung up.

Old Campus is the "hot zone," the area where the gunman is believed to be.

NBC Connecticut reported no shots have been fired and the search is very much open and active. State police, the Bureau of Alcohol, Tobacco and Firearms, the FBI and police from Yale and New Haven are all cooperating in the search effort.

CLICK HERE to WATCH NBC Conn.'s live coverage of the events at Yale.

The New Haven police and Yale confirmed the 911 caller told authorities his roommate was on his way to the school's campus to shoot people.

At least two people have confirmed seeing the gunman on campus, but still no one is custody, no shots have been fired and the scene remains active.

Law enforcement officials have advised the general public to stay away from campus and to avoid using the roads surrounding it, as they are shut down, causing heavy traffic.

Yale's latest official emergency update said campus police officers will be conducting room-by-room checks of several buildings. They will knock on the door, verbally identify themselves and then slip their ID badge under the door. Anyone occupying the room has been asked to cooperate, but the police may use keys in some circumstances.

In the press conference, Hartman said the ongoing investigation is of the utmost priority and will not be finished until a resolution is reached. He compared it to a flashlight that looses it battery power, flickers and shuts off. In this search effort, he said, that is absolutely not the case.

Latest updates from Emergency.Yale.Edu: (Twitter)

1:45 p.m.

Out of an abundance of caution, Police will be doing a room to room search starting with the residential college areas. When they knock on your door, a Yale Police Officer will slip their Yale ID under the door. Please cooperate. In some cases, Police may use keys, but they will identify themselves. Shelter in Place continues.

12:54 p.m.
There is no change in the campus status. We do not have additional information at this time. Those on campus should continue to shelter in place.

11:57 a.m.
There are confirmed reports of a person with a gun on campus on the Old Campus. The shelter-in-place/lockdown continues.

Teams from Yale Police, New Haven and the State Police are on the scene and are actively searching for any gunman.

THIS IS NOT A TEST. Call 911 with any information.