During an evidentiary hearing on Monday, the 27-year-old former Marine charged with allegedly stabbing to death an 11-year-old boy on his walk home from school began weeping as prosecutors revealed the child died from being stabbed more than 20 times, PEOPLE confirms.



A prosecution source tells PEOPLE that Andre Timothy Jackson, Jr. started shedding tears during Monday's court appearance. Jackson sobbed for less than 30 seconds, the source says, with his hands over his face for most of that time.



Jackson was arrested late last week for the alleged May 17 slaying of Josue Flores, a middle school student. Jackson did not speak during Monday's hearing.



According to prosecutors, Jackson allegedly told investigators he was the man captured on surveillance video footage running from the area of the crime scene. That video footage was released a day before Jackson's arrest.



Jackson also allegedly told detectives that he was at the scene of the stabbing on May 17.



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A prosecution spokesperson tells PEOPLE the alleged motive for last month's slaying remains a mystery, and that there is no known connection between Jackson and Flores.



"If we were ever able to determine a motive, like robbery, for instance, then the charges could be upgraded to capital murder," the spokesperson explains.



Jackson is being held on $100,000 bond and faces life in prison if convicted.



An attorney listed as representing Jackson in court records was unavailable Tuesday to comment on his client's behalf.



Authorities had initially arrested a 31-year-old man for Josue's stabbing death, but dropped the charges after detectives found evidence to support his alibi.