Florida shooting suspect Nikolas Cruz 'etched swastikas into ammunition magazines used in massacre'

Gunman was armed with 330 rounds when he opened fire on pupils and staff at Marjory Stoneman Douglas High School

Nikolas Cruz is arrested following the shooting at his former school

The Florida school shooting suspect had etched swastikas onto the ammunition magazines he used during the massacre, police have said.

Nikolas Cruz was armed with 330 rounds of ammunition when he entered Marjory Stoneman Douglas High School and began firing at pupils and staff with an assault rifle, according to law enforcement sources.

He left 180 cartridges behind unused when he dropped his weapon and escaped by blending in with fleeing students, unnamed officials told CBS News and CNN.

It is not yet clear why the gunman stopped shooting. Investigators believe his AR-15-style rifle may have jammed as he tried to reload during the 14 February attack, in which 14 pupils and three school employees were killed.

The magazine found inside the firearm was among those inscribed with the Nazi emblem, sources told the two broadcasters.

Mr Cruz, 19, is said to have worn a gas mask as he stalked the school with his firearm and smoke grenades before pulling a fire alarm, prompting students and staff to pour from classrooms into hallways.

Detectives believe he tried to create a sniper’s perch at the Parkland school, where he was a former student. Investigators found 16 rounds had been fired at a third-floor window, but the hurricane-proof class did not shatter.

A staff member at the school told CNN the room looks out onto the school’s car park and outdoor seating area.

Law enforcement officials have said Mr Cruz legally purchased the rifle about a year before the shooting. He was expelled from the school around the same time for a catalogue of disciplinary issues.

The Broward County Sheriff's Office responded to 45 calls about Mr Cruz or his brother between 2008 and 2017, records show, prompting accusations that authorities failed to act appropriately over warning signs. The reasons for the calls included “domestic disturbance”, “missing person” and “animal abuse”.

The FBI received at least two reports that Mr Cruz may pose a threat before the shooting. In addition, the agency was warned in September about a possible school shooting threat from a YouTube user with the same name as the suspect.

Mr Cruz has been charged with 17 counts of premeditated murder.