The victim, who was also in his 20s, was found dead in an apartment in the Majorna district on Thursday.
At a nearby cemetery, police were able to secure traces of blood and a bloodied object, according to GP. Investigators requested priority processing from the National Forensic Centre and received a DNA match on Saturday, linking the evidence to the suspected perpetrator. He was arrested the same day along with a teenage girl.
The girl's detention hearing is scheduled for Wednesday.