Mourning, Reflection Following Umpqua Community College Shooting

— -- Mourners gathered at a park in Roseburg, Oregon, Thursday, holding a vigil for the victims of the deadly mass shooting at Umpqua Community College.

The shooting left 10 people dead and at least seven others injured, according to the Douglas County Sheriff’s Office.

People gathered around 8 p.m. at Stewart Park in the city, which is located about 180 miles south of Portland. Attendees held up candles as the hymn "Amazing Grace" was played.

Authorities are trying to uncover the motive behind the shooting, which occurred just before 10:40 a.m. Three law enforcement sources briefed on the case identified the gunman as Chris Harper Mercer, 26.

Three pistols and an AR-style rifle were found at the scene, sources said.

It was unclear whether the shooter, who was killed in a gun battle with police, was counted among the 10 dead.

Ian Mercer, the suspected shooter’s father, briefly spoke to reporters outside his home Thursday, calling the situation a “devastating day for me and my family.”

Student Cassandra Welding was in Snyder Hall, in the classroom next to where the shooting occurred.

"I heard a really loud ka-pow noise, almost like a balloon popping, and we, all of our classmates, jumped and we did not know what it was," Welding said. "We knew something wasn’t right, and so a classmate of mine went to go open the door to see what was happening next door to where the shooting occurred, and she opened the door and, unfortunately, she got shot twice and she fell down and collapsed.”

The classmate was shot in the arm and abdomen, Welding said. The victim's friend performed CPR.

"I heard her breathing was really labored, she was like gasping for air, and we were just in frantic mode at that point," she said.

One of the victims, Chris Mintz, 30, is recovering from seven gunshot wounds. Witnesses say the student and Army vet charged at the gunman, trying to save who he could and telling others to run.

“He ran to the library and pulled the alarm and he was telling people to run, grabbing people, telling them you just have to go and he actually ran back towards the building where the shooting was,” student Hannah Miles said.

Kenneth Ungerman said he was outside Snyder Hall, talking to a National Guard recruiter when he heard a gunshot.

"I saw a male with a gun go around the corner to Snyder Hall," he told ABC News.

After that, he heard some more shots and ducked behind his Jeep. “Heard two more gun shots," he said. "People were screaming. We got out, heard more gunshots.

After that, the men told people in the parking lot to get out.

"We got down to the road and stopped traffic," Ungerman said, adding that he had military training. "We didn't want anyone else to go up to campus."

Kortney Moore saidshe was in a writing class when a bullet tore through the window, according to The Associated Press, citing the Roseburg News-Review.

She said the gunman came into the classroom, told people to get on the ground and then asked people about their religion.

President Obama, speaking about the massacre, lamented that mass killings have become “routine” in the United States and blasting those who oppose tougher gun laws.

“I hope and pray that I don’t have to come out again in my tenure as president to offer my condolences to families under these circumstances. But based on my experience as president, I can’t guarantee that,” Obama said in the White House briefing room.

The Associated Press contributed to this report.