Authorities continue to investigate who called in a bomb threat at a local doctor's office last week. A bomb detection K9's sweep of the property the morning of Dec. 17 found no proof of a threat, according to Dawson County Sheriff's spokesman Capt. Tony Wooten. "We did an initial sweep ourselves when the report was first called in, but also brought a bomb detection K9 in from another county to do a sweep, just as a precaution," he said.