Complex sentence: In March, April and May 1877, Siringo was in Dodge City, Kansas during a alleged confrontation between Clay Allison and Wyatt Earp, Earp was a Deputy Marshal at the time.
Split into simpler sentences: In March, April and May 1877, Siringo was in Dodge City, Kansas. It was during this period that he was present during a supposed confrontation between Clay Allison and Wyatt Earp, Earp being the Dodge City Deputy Marshal at the time.