Oct 20, 2009 2:06 PM by Associated Press
As sheriff's investigators in Colorado continue their probe of last week's alleged balloon hoax, the Federal Aviation Administration has opened its own investigation.
A spokesman says the probe began either Friday or yesterday, but he didn't know how long it would take.
He says the FAA investigates civil allegations, rather than criminal ones.
The balloon landed near Denver International Airport, and some flights had to be changed to a different runway for 20 minutes.