Parker and Caroline Lofgren and their children were delighted to win a fundraising auction at their kids' school for a vacation in a $9 million Aspen, Colo., mansion.
The newly built 3,250-square-foot house had three bedrooms, three full and two half bathrooms and private river access.
It also had a faulty pipe in the heating and snow melt system, which leaked carbon monoxide and killed the family while they slept, according to investigators.
Now police are sending technicians and detectives to the house to determine whether anyone is at fault for the deaths.
Pitkin County Sheriff's Office Detective Marie Munday told ABCNews.com that the cause of the carbon monoxide appears to be a disconnect in the heating and snow melt system where the PVC piping was not glued together.
The Lofgrens decided the week before Thanksgiving to spend the holiday weekend with their two children, Owen, 10, and Sophie, 8, at a the home outside Aspen near the picturesque Independence Pass.
Their bodies were found Friday in one of the bedrooms where they had been sleeping. The grisly discovery was made by friends who had arrived at the house to spend a few days with the Lofgrens before they headed home.
The family was a close-knit group of accomplished skiers, according to Scot Wetzel, a good friend who has been acting as the family's spokesman.
"They were actually supposed to be with us for Thanksgiving," Wetzel told ABCNews.com. Instead, they headed up to the house in Aspen after winning a stay there during a fundraising auction at the children's school.
Parker Lofgren "was my best friend," Wetzel said. "We shared everything."
'Immeasurable' Loss of Life
Ross Buchanan, a Denver-based personal injury and product liability lawyer, said that he could only speculate as to where this case will go now, but that his first look would be at whoever didn't properly glue the PVC piping together, likely a contractor.
Construction law in Colorado has its own set of liability laws, he said, and claims typically deal with property damage not human death.
"The loss of life is immeasurable," he said.
There's also a possibility, he theorized, that even the manufacturer of the faulty equipment -- maybe the glue or pipes, if it wasn't working properly -- could also be held liable.
Buchanan said he doesn't see how St. Anne's Episcopal School, which auctioned off the stay in the house, could be liable under Colorado law because it was not responsible for the house's condition.
But, he said, the owner of the property could possibly face liability under Colorado law that would likely classify the Lofgrens as "invitees." In that case, the owner of the property could be held liable for any dangerous conditions the owner knew about or should have known about.
"To me that's a very significant question in this case, whether the owner had any inkling," Buchanan said. "I'm assuming he didn't. But should he have known?"
The house is owned by Jonathan Thomas of Meyer Holding Corp. A man who answered the phone at Meyer Holding said the company was not commenting on the deaths and a call to a listing for Thomas on Popcorn Lane, down the street from the house the Lofgrens were staying at, went unanswered.
The owners had reportedly been in the house the weekend before the Lofgrens' visit and experienced no problems.
It was unclear whether or not the house had a carbon monoxide detector as required by 2004 state law. There was no audible alarm when police responded, Munday said.
"A detective is going to go check on that," Munday said. A technician will also be brought in to determine whether anyone is at fault for the carbon monoxide leak.
Final toxicology screens on the Lofgren family could take up to two weeks.
The carbon monoxide levels found in the house were extremely high when emergency workers responded. The undersheriff, Munday said, complained of a headache shortly after he arrived on the scene and got everyone out quickly. The family who found the Lofgrens was not treated for carbon monoxide poisoning.
According to the U.S. Environmental Protection Agency Web site, carbon monoxide, produced by burning oil, charcoal, wood, gas or kerosene, can kill in minutes at high levels. Symptoms include dizziness, headaches, nausea and feeling faint or mentally confused.
The EPA recommends having heating systems inspected at the beginning of each heating season and installing appliances that vent to the outside of the building. Anyone who suspects carbon monoxide poisoning should get fresh air immediately and seek medical attention.
The Popcorn Lane house where the Lofgrens stayed is listed for sale for $8.95 million through Morris & Frywal Real Estate in Aspen.
The listing also says there are permits and plans for a 7,021-square-foot main house for which the foundation has been dug.
Listing agent Craig Morris did not return messages seeking comment. A woman who returned a call on his behalf directed ABCNews.com to the house listing and said Morris had no further comment.
Wetzel described the Lofgren children as "very intelligent and very special children." Both started skiing lessons at the age of 4 and had already worked their way up to double black diamond trails.
Owen started competitive ski racing last year while Sophie was an accomplished violinist.
Parker Lofgren was a founding partner of the high-profile boutique investment bank St. Charles Capital and was involved in merger and acquisition investments worth in excess of $2.3 billion, according to a news release issued by the company.
Caroline Lofgren, Wetzel said, had worked in risk management before leaving her job to stay home with the children after Sophie was born. According to the St. Charles Capital Web site, Caroline Lofgren, a graduate of the University of Vermont, was involved with several philanthropic causes, including Girls Inc. of Denver, The Colorado Symphony and Historic Denver.
Wetzel, the CEO of United Western Bancorp. in Denver, said he was up early Saturday morning reading the local newspaper when he noticed a small article in the back about a family of four with a boy and a girl who had died while vacationing in an Aspen home.
"As I was reading it, I was getting worried," he said.
Wetzel said he was in the middle of sending Parker Lofgren a text message to check on the family, fully expecting to get grief from his friend for waking him up, when a mutual friend called to tell him that the Lofgrens had died.
'Wonderful Members of Our Community'
Wetzel said he last spoke to his best friend on Wednesday. He left a voice mail wishing the Lofgrens a happy Thanksgiving on Thursday, but didn't hear back from him. Local media reports said the last time anyone heard from the family was on Thursday afternoon when Caroline Lofgren had sent out text messages.
Alan Smiley, head of St. Anne's Episcopal School where Owen and Sophie were in fourth and third grades, said they held a private prayer service for students, parents, staff and the community on Monday morning and that a team of grief counselors will be at the school all week, longer if need be.
"It's obviously been a terribly tragic and difficult loss for our entire community," he told ABCNews.com
He described Owen as a bright child who "absorbed learning in all its different shapes and forms" while Sophie was "bubbly and energetic" and participated in lacrosse and swimming.
"They were beloved kids," he said. "Just wonderful members of our community."
He declined to comment further on the auction that netted the Lofgrens a stay in the Aspen home.
Funeral services are scheduled for Friday in Denver.