Two young attackers killed three people at the largest mosque in San Diego County, a tragedy for the Muslim community and a likely hate crime.

• Two shooters, aged 17 and 18, opened fire at the Islamic Center of San Diego on May 18, killing three victims before dying themselves in a car nearby.
• Police are investigating it as a possible hate crime and arrived within four minutes of the first 911 calls.
• A security guard named Amin Abdullah is being called a hero for confronting the shooters and triggering the lockdown.
• About 140 children inside the mosque school were protected during the lockdown while parents waited in fear.

Outlook: Investigators will look at the shooters' motives and online activity, and pressure for tighter mosque security across the country is likely to grow.