Federal investigators have recovered a total of 13 weapons possessed by the lone gunman who went on a shooting rampage at a community college in rural southern Oregon, including six firearms recovered at the school and seven at the gunman's apartment.
"All the guns were purchased legally and traced to the same firearms dealer," Celinez Nunez of the federal Bureau of Alcohol, Tobacco, Firearms and Explosives said Friday. She said at a news conference that some of the weapons were were purchased by the shooter, while others were not.
The weapons recovered at Umpqua Community College in Roseburg, Oregon, included five pistols and a rifle.
Douglas County Sheriff John Hanlin told reporters at the same Friday news-conference that teams of investigators are working with each of the victims' families individually to give them personal attention.
Earlier, Hanlin said investigators were at the college and the shooter's nearby apartment throughout the night and during the morning hours.
Officials identified the gunman as 26-year-old Chris Harper Mercer and said he opened fire at the college Thursday, killing nine people and wounding nine others before dying during an exchange of gunfire with officers.
Hospital officials said two of the wounded are in stable condition and one is being moved out of intensive care.
Law enforcement officials said Mercer had three weapons, at least one of which was a long gun, and that the others were believed to be handguns. Hanlin said investigators would release details on the number and types of weapons later Friday.
Police are also planning to investigate the shooter's blog posts to determine a motive.
Meanwhile, witnesses to the rampage said the shooter was targeting Christians. At least two witness accounts said the shooter asked his victims if they were Christian before he shot them.
At least two witness accounts say the shooter, who has not been named by law enforcement officials, asked his victims if they were Christian before he shot them.
Authorities believe the gunman was familiar with the college and the building. They also say he wrote on a social media website about what he was planning to do.
But investigators believe this was a case of domestic terrorism with no ties to any international group.
Douglas County Sheriff John Hanlin spoke to the media late Thursday, providing details of the shooting but asked reporters not to give the shooter undue publicity by using his name.
Hanlin said, "we think we know who the shooter is," but added, "I will not give him the credit he probably sought prior to this horrific and cowardly act." He encouraged members of the media to avoid using, repeating, or sensationalizing the shooter's name once it is confirmed.
WATCH: Obama: 'Americans have become numb'
An angry U.S. President Barack Obama responded to the shooting within hours, appearing on television demanding that the American people push Congress to pass "common sense" gun laws. He said the majority of Americans, including law-abiding gun owners, want tougher gun laws.
He said Americans have become numb to what has become routine in the U.S. -- a mass shooting, followed by his White House statements, and the response by those who oppose more gun control. He said the argument that more guns make people safer cannot be made with a straight face.
"The [National Rifle Association] doesn’t represent the majority of the American people, but they’re very effective. The American people are going to have to match their sense of urgency," Obama said.
He said the majority of Americans, including law abiding gun owners, want tougher gun laws.
Sheriff Hanlin said many law enforcement agencies, including the FBI, are involved in the investigation. Officials are making sure the campus is safe and are looking for a motive.
Shooting aftermath
The interim president of the Oregon community college, Rita Cavin offered her condolences to the families of the victims and "the families of anybody who was hurt . . . emotionally or physically." She said late Thursday that it had been "a long, sad, tragic day" at the college and thanked the many people she said rushed to the aid of the school and its students and staff.
Sheriff Hanlin said many law enforcement agencies, including the FBI, are involved in the investigation. Officials are making sure the campus is safe and are looking for a motive.
Sheriff Hanlin called Thursday's incident a "huge shock" to the quiet rural county, where few residents are strangers.
About 3,000 students attend Umpqua Community College. Fifty-eight percent of them are female. Most of the students are 30 and older who go to the school part-time to prepare to change careers.