Ahmad Al Aliwi Alissa was already charged with 10 counts of attempted murder, murder and weapons offenses
On Wednesday, prosecutors added another 44 counts to the indictment
Alissa is now charged with 54 counts; he is being held without bail in jail
On March 22, he shot dead 10 people at the King Soopers in Boulder, Colorado
His motive remains unclear - he had been bullied in school and was described by family as a 'loner' who'd never had a girlfriend