(しわざ)

しわざ
noun
act; deed; doing (usually negative)
action
1. act, deed, doing, work (usually negative or mischievous)
An action or deed, almost always used to attribute blame or responsibility for something bad or mischievous.
これ(だれ)仕業(しわざ)だ?
Who did this? (Whose doing is this?)
The garden was probably messed up by a cat.
The police believe this incident is the work of a criminal organization.

Common patterns

Usage: Almost exclusively used in negative contexts — mischief, crime, damage, or blame. Rarely used for positive actions. Common in mystery stories, news reports, and when attributing blame.

Note: Can also be used humorously for minor mischief: 菓子(かし)()えた()ども仕業(しわざ)だ (The disappearing sweets were the children's doing).