Five other occupants of the vehicle were transported to hospital, two in critical condition and three in a serious condition.
Police said today the crash was still under investigation.
A source has told the Herald that Karl and the others in the car - including one person travelling in the boot - had been attending a 21st.
Police could not comment on the specifics of the crash and said earlier this week the other injured occupants of the car were yet to be interviewed.
"Police extend their condolences to his family and friends," a spokesperson said in a statement today.
"Inquiries into the circumstances of the crash are ongoing."