A shooter opened fire at YouTube's headquarters in Northern California on Tuesday, leaving at least three people injured and one woman - the suspected shooter - dead.

A 36-year-old man was in critical condition, a 32-year-old woman was in serious condition, and a 27-year-old woman was in fair condition, according to The Independent.

On 14 February this year, 17 people - including 14 students and three members of staff - were massacred by a shooter at a high school in Parkland, Florida.

Just a few months before, in November 2017, a gunman opened fire on a church in Texas and killed 26 people and injured 20 others.

The attack happened at the First Baptist Church in Sutherland Springs, with victims ranging from the age of five to 72.

The BBC report that 26-year-old Devin Patrick Kelley was identified as the shooter by US media. He was found dead from a gunshot wound a few miles away. No motive for the crime has been confirmed at this time.

Kelley is said to be a former member of the US Air Force and had received a court-martial in 2014 for assaulting his wife and child.

The incident has already been confirmed as the worst mass shooting in Texas history. The shooting followed the largest mass shooting in recent US history in Las Vegas, which claimed 59 lives and injured hundreds.

Since the Sandy Hook elementary school massacre in December 2012, there have been at least 1,625 mass shootings - with at least 1,862 people killed and 6,529 peopled wounded - in the US, according to the Gun Violence Archive.

Michael Skolnik, who is a civil rights activist and news commentator used that fact and another to highlight just how big a problem this is for the US and the lack of effort that has been made by politicians to introduce stricter gun laws.

The shoe bomber refers to Richard Reid, a British man who attempted to detonate a plastic explosive hidden in his shoe on a flight from Paris to Miami in December 2001.

His efforts failed but it caused US airports to introduce procedures that meant passengers have to remove their shoes when passing through security scanners.

This protocol has since been adopted by other major airports around the world.

It remains to be seen whether the US Congress will act to introduce tougher gun control after this latest shooting.

In a now infamous speech, Barack Obama asked Congress to address America's gun problem in January 2016 but the action failed to win enough support.