Had this been another day, they would have directly used this excuse to invade the Elves and purge them. Oh, you can be sure that the Gods had been looking for an excuse to do so, but those damn Elves were always minding their own business, never causing any trouble.
Even if this lone Elf had no affiliation to the rest of his/her race, who cared?
The Gods would just declare that the Elves were lying, and it would simply become a matter of word of mouth.
This was how they, the Gods of Faust, operated!
They would identify a possible interest or problem. Then, they would find a morally justified reason to attack/invade the location of the item of interest/problem through their army of believers.
After that, a slaughter would occur if necessary. Once the Gods had claimed the item of interest/problem, they would then share the spoils of everything among themselves.
If you had a dissenting opinion, that was not an issue.