In San Bernardino, California, thousands gathered Thursday night at a local stadium for a candlelight vigil to mourn those killed in Wednesday’s mass shooting at the Inland Regional Center, a facility that provides services to people with disabilities. President Obama ordered flags lowered to half-staff at public buildings across Washington, D.C. The FBI counterterrorism unit is overseeing the investigation, although the agency has said it has not yet determined whether terrorism was a motive in the shooting. One of the suspected gunmen in Wednesday’s shooting, Syed Rizwan Farook, was a county health department employee who had attended a department holiday party at the center earlier in the day and left after some kind of dispute. He allegedly returned to the party with his wife, Tashfeen Malik, and a cache of weapons and opened fire. It was the worst mass shooting in the United States since the shooting at Sandy Hook Elementary School in Newtown, Connecticut, when a gunman killed 20 children, six adults, his mother and himself. On Thursday, members of the largest mosque in San Bernardino County held a vigil for the massacre’s victims. Local Muslim leader Ahsan Khan expressed the community’s grief.

Ahsan Khan: “We, as Muslims of the Ahmadiyya Community, are gathered here tonight in a state of grief after the horrific events that transpired in our neighborhood of San Bernardino County yesterday. First and foremost, our message is to the victims and their loved ones. We extend our heartfelt condolences to you and everyone who suffered yesterday. The Holy Qur’an, the book of God that you just heard recited, it teaches us that the killing of an innocent is like the destruction of all of mankind.”