It is a long story but essentially there seem to be a key person who deceived them all, including his colleagues: someone by the name of Allen West, formerly Allen Whitt, a former convict for pretending to be a geologist and scamming municipal authorities out of that.
After getting out on probation he began working on the comet theory and changed his name legally. Then somehow he managed to be part of both teams that have published anything defending the Clovis impact theory (mentioned by me here and here).
In the second case I thought it was a different team working in a different part of the World. And it was indeed but one person at least was part of both teams: Allen West.
His carbon spherules, sometimes called nanodiamonds, appear to be just graphite and not older than 200 years old.