Reports of the Alkali Lake Monster started in August of 1921, and the first written account of the monster appeared in a 1922 printing of the Hay Springs News.
Then in 1923 another report appeared in the Omaha World Herald. According to this report J.A. Johnson claimed that he and two friends saw the creature while camping on the shores of
See the original news report here dated 1923 July 24th :
There seems to have been no more sightings since the 1920’s , so unless the creature died out or it was a hoax, there is no more evidence. One thing I did come across was that there had been a drought in the 1880’s/90’s that almost completely dried up the lake so any large creature in it could only have appeared after that time. Maybe an escaped crocodile from a circus ? Unless there are other appearances we will never know