BERLIN — It was a most surprising case for the police: An endangered bird may have attacked two men in a forest, they attacked and killed the bird, and a crowd attacked the two men. Less surprising, alcohol was involved.

Now, with the body of a western capercaillie as evidence, the authorities in southwestern Germany are trying to determine what happened, and whether anyone involved committed a crime.

Returning home from a festival on Saturday, two young men, both drunk, took a shortcut through the woods, when they encountered the bird and beat it with a bottle, according to the police in Titisee-Neustadt, the Black Forest village where the incident occurred.

They later said they were merely defending themselves from the capercaillie, also known as a wood grouse or heather cock, which is roughly the size of a large chicken. In keeping with German law, the men, aged 22 and 20, were not identified.