A Pitkin County Sheriff's investigator says a plastic pipe that should have been connected to a gas-fired water boiler was the reason for a carbon-monoxide leak that killed a family of four in Aspen.

Investigator Brad Gibson says the leak was in a utility room but it spread to through the home on Nov. 28. The family had won a weekend vacation at the Aspen home through a fundraiser.

Killed were Parker Lofgren, 39, Caroline Lofgren, 42, and their children, 10-year-old Owen and 8-year-old Sophie.

Officials are not saying whether the home had a carbon-monoxide detector and Gibson says investigators are trying to determine how the pipe came undone.

State lawmakers this session will consider whether all homes should be required to have carbon-monoxide detectors.