The rifle magazines Nikolas Cruz used in a deadly school shooting earlier this month reportedly had swastikas etched on them.

A law enforcement source told CBS News that Cruz had etched swastikas on to the ammunition magazines of the AR-15 rifle he brought to Marjory Stoneman Douglas High School in February 14. CBS News also reports that Cruz had 180 rounds of ammunition left when he abruptly dropped his weapon, took off his vest, and filed out of the school, blending in with evacuating students.

It is not known exactly why he stopped firing. Based on earlier reports that he fled the school building before law enforcement agents entered, he does not appear to have been interrupted by police. According to CBS News, investigators reportedly believe Cruz may have stopped shooting when his weapon jammed as he was trying to reload a new magazine.

Investigators reportedly told CNN that Cruz confessed to the deadly shooting on the same day of the massacre. He is facing 17 counts of premeditated murder.

[Feature image: Nikolas Cruz/Broward County Jail]