This graffiti is the work of a kid from the neighborhood.
いたずらは弟の仕業に違いない。
The prank must be my little brother's doing.
The candy disappearing from the fridge must be my little brother's doing.
The scratch on the wall seems to be someone unknown's doing.
所業 is a literary, rather old-fashioned word for one's deeds and usually implies wrongdoing, whereas 仕業 is the everyday word used the same way.
犯行 specifically means a criminal act, while 仕業 is broader and can describe any mischievous or blameworthy deed, not necessarily a crime.
仕草 (a gesture or mannerism) looks similar to 仕業 (a deed, often blameworthy) but the two refer to completely different things.
Standard kanji spelling; the most common written form.
Rarely used kanji form; learners will almost always encounter 仕業.
Compound of 仕 (し, 'to do') and 業 (わざ, 'work, deed'). The reading しわざ is a straightforward combination of the on'yomi of 仕 and the kun'yomi of 業.