The 13-year-old had tempted the piglet with a piece of bread and he and three other friends (aged 14 and 11) pelted it with stones, and he then strangled it with a piece of rope.
When the mother boar tried to defend her young, they threw stones at her as well.
Witnesses who observed the boys called the police, who sadly arrived on the scene too late to save the piglet.
When police interviewed the boys the 13-year-old confessed to the crime, and said he did it because “he was bored”.
Two 14-year-olds were arrested for animal cruelty but the 13 and 11-year-old were taken home to their parents. They cannot be charged as they are minors, and therefore not considered criminally responsible.
A few days before their shocking act of cruelty the same boys are reported to have threatened a forester in the same park , and said they would “stab him”.
The Lainzer Tiergarten, in the southwest of Vienna, is home to between 800 and 1,000 wild boar, as well as fallow and red deer.