Mr. Mintz “tries to block the door to keep the gunman from coming, gets shot three times, hits the floor, looks up at the gunman and says ‘It’s my son’s birthday today,’ gets shot two more times,” Wanda Mintz, his aunt, told WGHP.

A cousin, Ariana Earnhardt, said, “His vital signs are O.K., I mean, he’s going to have to learn to walk again, but he walked away with his life, and that’s more than so many other people did.”

On a recording of emergency workers’ radio traffic, six minutes after the initial call of a shooting, a police officer can be heard saying: “We’re exchanging shots with him. He’s in a classroom on the southeast side of Snyder Hall.”

Just over two minutes later, an officer shouted, “The suspect is down.”

The shooting renewed the heated debate over gun control that has followed mass shootings in so many parts of the country, with President Obama speaking emotionally on Thursday, and again on Friday, calling on Congress to take measures to curb gun violence. But Oregon’s top elected officials, Democrats in a state where guns and hunting are popular, took a much more cautious tone on Friday.

Speaking at a news conference here, Gov. Kate Brown and Senators Ron Wyden and Jeff Merkley all said some steps should be taken, but that now was not the time to decide what those should be, or even to discuss them. And all avoided using the phrase “gun control.”

Mr. Merkley, who was born in Douglas County and lived here for the first several years of his life, said one of the people killed at the college was a cousin. “This horrific, this senseless act, has broken hearts, every heart here,” he said.

Through the day Friday, more than 100 law enforcement officers continued to comb through the crime scene and interview witnesses and people who knew the gunman. Sheriff John Hanlin of Douglas County refused to say the gunman’s name and vowed that even as it was released by other agencies, it would not be uttered by his department. Echoing a position taken by officials in some other places rocked by mass shootings, he said he would not give the gunman the fame he craved, and asked journalists to follow his lead, rekindling an old debate about the role of the news media.