The poor “student” was just playing a game of garage-hopping. It is a harmless game where “students” look for things of interest in people’s garages and take them. The “student” was just minding his own business when he died in an unprovoked attack.
Kaarma had him cornered, toyed with him, and then executed him - although he had the foreknowledge, time and opportunity to call the police, who would have caught Dede redhanded.
The student committed burglary. Kaarma committed murder.