Traveling by train, Butler's forces reached the outskirts of Masaya, where they were threatened by rebels led by Benjamín Zeledón atop the hills of Coyotepe and Barranca.

[15] Before long, snipers in the houses on both sides of the railroad track[16] and 150 "armed horsemen"[17] began shooting at the American-occupied train.

The U.S. forces, both inside the train and outside (taking cover alongside the roadbed),[18] including the machine gunners on top of the boxcars, "returned fire.

"[22] The train now started picking up steam, leaving behind the Marines, led by Captain Nelson P. Vulte, who had sought refuge by the roadbed.

"[28] However, the Masaya ambush, called "an act of treachery on the part of General Zeledón," was allegedly "premeditated" and "carefully planned.