The shooting at Northern Illinois University has claimed five lives and left a lasting impression on survivors. BBC News website readers give their accounts of the day everything changed on the NIU campus.
TONY HOGAN, COMPUTER SCIENCES MAJOR
At the time of the shooting I was on the main street of campus in my car on my way to pick up my girlfriend from class.
As I got closer to her building, multiple police cars sped past me along with an ambulance. I knew something was wrong.
Emergency workers were on the scene within minutes
Once I got closer, all the major roads leading to campus were cornered off by police vehicles.
I realised then that I could not get anywhere near my girlfriend's building so I called her.
I told her something really bad was going on and she told me there had been a shooting. When I asked her how she knew, she told me that she had seen a guy who had been shot in the leg being interviewed by the police.
Numerous people were running away from the building when the shooting began. Luckily my girlfriend was safe in the building next door, but, sadly, many others were not.
When she finally made it out of the building and past the police, we got stuck in traffic. It took a long time to get back to the apartment. My girlfriend is pretty calm now, but she was all nerves when she got into my car.
As a student of the school I am truly devastated by this tragedy
When you hear about campus shootings, you never think it will happen at your school. You cannot get your mind around the idea of it happening. We have a friend who was in the room where the shooting took place. We spoke to her though and she seems to be OK.
The day after the shooting we are trying to keep away. The campus is closed and it would be impossible to open it until at least late in the week, certainly not the room where it happened, the windows are smashed out.
We cannot really do anything and that is what makes it odd.
My prayers and thoughts go out to the families of those injured and killed. As a student of the school I am truly devastated by this tragedy.
BRIAN GIBSON, WHOSE DAUGHTER IS STUDYING IN ILLINOIS
When we heard the news and it mentioned Illinois, our ears pricked up - my wife, son and I all looked at each other. They had mentioned a shooting.
Then they mentioned DeKalb and your heart misses a beat; my daughter is studying in Illinois, Decatur. You wonder if you heard right.
All the kids out there were really shocked
When there are so many campus shootings you tend to worry a little bit. Our daughter won a scholarship to study in America as part of her law degree.
When you realise, you then feel relieved, and guilty at the same time as some other equally innocent family have been thrust into a world of hurt and pain, and why? Because some unbalanced individual has a grievance.
We spoke to our daughter briefly after it had happened. The time difference means mostly we have short calls to keep in touch. She was fine, her campus is much further south, but from over here it seems so close. She told us she was OK, but that all the kids out there were really shocked.
I am so sorry this has happened.
AN NIU STUDENT
I was standing at the bus stop about 20 yards from Cole Hall waiting for a bus and talking to a friend. I had gotten out of class early.
All major roads to the campus were blocked off by the police
We heard a few pops, about 3pm, and turned. I didn't recognise the sound at first, but people began streaming out of Cole hall, and yelling "He's got a gun." I took off away from Cole Hall, running away from campus.
When I got through the parking lot and thought I was safe I turned around and decided to go to the student centre. There was nothing "heroic" in it, it's just a reaction I had.
I heard over a police scanner that they needed paramedics and were treating people in the bookstore, at about 3.15. I went down to offer any assistance I could, but by the time I was able to go, more paramedics had arrived and I wasn't needed.
Most of the injuries were to the torso and abdomen. I vividly recall one woman bleeding very heavily from her chest.
At about 3.20 I was asked to keep an eye on some of the victims and witnesses that police began to retain for interviews.
Students and staff at the university held vigils to mourn victims
While doing that, I helped one young lady who had bird-shot stuck in her forearm. That's when I knew the attacker had used a shotgun.
It made it seem so much more inhuman to me, because he was trying to damage as many people as possible, and it looks like he did just that.
The look on those people's faces was the most horrible thing I've ever seen. They were all looking for friends, and when they couldn't find them, they went hysterical.
Today on campus is strange. People aren't afraid, but the tension is palpable, and the shock is intense.
One of the most stirring things I saw was leaving my job last night, a group of a few hundred students had spontaneously gathered outside a fountain by my building, and were singing Amazing Grace. I cried the whole way home.
I saw a lot of terrible things yesterday, the worst of humanity. I'm coping because I know I saw far greater things last night.
In the face of such tragedy, in such despair, I also saw the best of humanity. There was so much love on campus, and so many people that care.
STEVE, NIU STUDENT
I found out at around 3.15 when a friend sent a text message to me from her classroom which was in lockdown. At that point it was known that two people had been shot. There was nothing I could do then as I was at work, in Chicago.
Victims were taken through the snow to waiting ambulances
By the time I got home there were still state and local police all over the campus, by the crime scene, near the dorms, everywhere. There was at least one state trooper carrying an M16 at a roadblock.
I think that, emotionally, the timeliness of the response of the emergency services and having the police there made people feel that things would be OK.
I can see Cole Hall from my apartment window, and there was bright light illuminating the area while the police worked into the night. The roads leading up to the dorms were clogged with parents picking up their children.
Today I walked around the campus. There are fewer students than usual, more police and there are media trucks around with antennae.
People are starting to organise vigils and lay flowers. Some get closer to the crime scene tape; you can still see the footprints in the snow where people ran out of the building.
The campus feels safe but sombre.
MIKE SALMOND, ART PROFESSOR AT NIU
I was on campus, in class at the time of the shootings. We found out first through a text message sent to a student in my class, from a friend.
Shortly after the shooting, there was a moment of incredulity, then more texts and calls came in. There was a confusion of information, with an overlap of different locations and the size of the event.
Students console each other on campus
The NIU information response was very quick. We were told to lock ourselves into our classrooms and wait for an all-clear. As I teach time arts we quickly plugged into the CNN/Media feeds.
My students (advanced video) seemed to hold themselves together very well but I did see a few very distressed students when the news first broke. It was certainly one of those "It can't happen here surely?" moments.
The event was at the centre of campus, which is quite a distance from the Arts building. Most students cellphones were useless as all the lines became clogged fast (DeKalb is a small rural area with a university taking up a huge part of it). I monitored one student at a time to a safe area where they could contact families (locked area to locked area).
I hope the strong community of NIU can overcome this tragedy
When we were given the all-clear on the website and had confirmation, faculty let students out. There was much disbelief and just plain incredulity really.
Leaving campus a few hours later it was certainly disturbing and weird to see police armed with rifles and machine guns closing off the NIU campus.
It's another US campus tragedy but I have to admit the way NIU dealt was very organised, or as organised as anyone could expect in such an event. I hope the strong community of NIU can overcome this tragedy and become stronger for it.
MICHAEL IBRAHIM, CHICAGO RESIDENT
I myself go to the University of Illinois, but I have many friends that go to Northern Illinois University.
Friends say they are still in shock and some personally knew a victim.
On my campus there's usually more laughing, more students, but not today
I have been trying to get hold of a friend of mine who has not yet responded to e-mail and phone calls, unlike all of my other friends at the school. It turns out she was out of town at the time; she might be better off having missed the whole thing.
On my campus there's usually more laughing, more students, but not today. It's quiet. The bells usually play something upbeat on a Friday, but at 12pm they played Amazing Grace, then nothing more.
COURTNEY GONSOWSKI, SOPHOMORE AT NIU
I was on campus when the shooting took place. I was in a classroom in the building next door.
Emergency hotlines and counselling are available to students
We were all forced to stay locked inside and wait out whatever was going on. Once we were told that our classroom would be locked down, pretty much everyone whipped out their cellphones to try and contact someone outside.
I managed to reach my boyfriend and my best friend and tell them I was OK so that they could forward that message.
We saw the police running into Cole Hall with what looked to be rifles, and we saw the ambulances arrive with stretchers. People in my class started to cry and freak out.
From where I was, I saw five bodies being taken away on stretchers. I cannot even convey with words what I have seen today.
I am reluctant to go back to the campus at the moment. It's closed at the moment but every time I close my eyes, all I see are the wounded.
This event is horrific and extremely sad. Those who passed will be genuinely missed by the entire NIU community.