I've been talking to the police directly, and nothing is conclusive yet. Nothing has actually been ruled out, nor determined to be the cause. They don't even have full toxicology reports yet, those take days and sometimes weeks.
On a personal note, I can tell you that there were two devices in the house, a small 3D printer, and a small laser cutter, that were used for building models and rigs for scientific research. Val was an immaculate engineer, and conformed to all safety rules in operating these machines. To the best of our knowledge, neither of the machines were operating the night they passed away.
Again, please refrain from fear-mongering and speculation. I know it's natural for engineers to attack unsolved problems, but you are not working with correct or full data. Once more data is available, we will write up a complete and truthful statement to try and provide closure on this issue.