Authorities were still piecing together a motive and the circumstances that led up to the stabbing of Deeds, the Democrats' gubernatorial nominee four years ago.
"We're leaning towards it being an attempted murder/suicide," Virginia State Police spokeswoman Corrine Geller said at an afternoon news conference. However, she said that finding wasn't yet definitive.
Deeds' 24-year-old son, Gus, died at the home of a gunshot wound. Geller said Creigh (kree) Deeds and his son were the only people at the home Tuesday morning and they were not looking for a suspect.
The senator, known for his reserved demeanor and humble farmland roots, was in fair condition at a hospital Tuesday afternoon. He had previously been listed in critical.
Deeds made his first bid for statewide office in 2005 when he ran for attorney general and narrowly lost to current Gov. Bob McDonnell in the general election. Four years later, McDonnell beat Deeds again in the race for governor, though by a much wider margin.
After the stabbing, Deeds was able to walk away from his home to a nearby road in rural western Virginia and a cousin who was driving by happened to spot the senator, police said. They drove to the cousin's home and 911 was called from there.
Inside the senator's home in Millboro, authorities found Gus Deeds suffering from a gunshot wound. Despite efforts by state troopers and first responders, he died there.
She said police have been able to talk with the senator, but Geller wouldn't reveal what he has said.
Deeds, a former Bath County prosecutor, was elected to the House of Delegates in 1991 and to the state Senate in 2001. He ran for attorney general in 2005, but lost to McDonnell, a Republican. The margin of victory was fewer than 400 votes out of nearly 2 million cast.
Deeds and McDonnell squared off again in 2009 in the race for governor after Deeds defeated Terry McAuliffe and Brian Moran in the Democratic primary, but Deeds lost badly in the general election.
Gus Deeds is one of the senator's four adult children. He was studying music at the College of William and Mary, where he had been enrolled off and on since 2007, but withdrew last month, school spokesman Brian Whitson said. The college said he had a strong academic record. It did not say why he left.
During Deeds' bid for governor, his son took off a semester to join his dad on the campaign trail.
"He needs me and I need him," Deeds told a reporter in the fall of 2009, about campaigning with Gus.
"I've got to go through this campaign process but that doesn't mean I've got to be completely separated from my family the whole time," he said.
Del. David Toscano, D-Charlottesville, whose district overlaps with Deeds', said in a statement: "Sen. Deeds was very close to his son, Gus, and has taken herculean efforts to help him over the years. Our thoughts and prayers are with Creigh and the family at this difficult time."
McDonnell said in a statement the news was "utterly heartbreaking."
"Creigh Deeds is an exceptional and committed public servant who has always done what he believes is best for Virginia and who gives his all to public service," McDonnell said.
McAuliffe, now governor-elect, called it a sad day for Virginia.
"We join people across the Commonwealth and country in wishing him a full recovery," he said.
Deeds and his ex-wife, Pam, divorced shortly after the 2009 campaign. Deeds remarried last year.
Deeds' reputation among colleagues has been as a thoughtful legislator. On social issues, he is generally to the right of party liberals, supporting abortion rights, but opposing gay marriage and gun control measures. He wrote a constitutional amendment guaranteeing Virginians' right to hunt and fish.
He proved to be a reserved campaigner in 2009, described as shy by his fellow lawmakers.
"I don't like fundraising. I don't like being away from home all the time," he said during the campaign. "I enjoy the service. I enjoy the work that politics allows you to do. I don't know that I really enjoy the process that much."
Deeds spent most of his childhood in Bath County, where his family settled in the 1740s. The rural county is known for the high-end Homestead resort, but Deeds grew up on the other side of the mountain.
"I didn't grow up on the end of the county where you learn to ski and play golf as a child," he said. Deeds lived on a farm after his parents divorced when he was about 7.
His grandfather was the Democratic Party chairman in Bath County during the Great Depression.
Associated Press writer Matthew Barakat contributed to this report from McLean and writers Larry O'Dell and Michael Felberbaum contributed from Richmond.