While authorities were still trying to determine the motive behind the shooting spree in San Bernardino, California, that killed 14 people Wednesday, American Muslim community groups condemned the massacre and urged the public not to blame Islam or Muslims in general.

The suspected attackers, both killed by police, have been identified as Syed Farook, 28, and Tashfeen Malik, 27, a Muslim couple who had a 6-month-old child. Farook worked at the San Bernardino County health department facility targeted in the shooting.

“We don’t know the motive yet,” Hussam Ayloush, executive director of the Los Angeles area’s Council on American-Islamic Relations (CAIR), told NPR on Thursday. “This could be workplace rage, it could be the result of some mental instability, or it could be some twisted ideological belief,” he added. “Either way, it’s horrific, it should be condemned; there’s absolutely no justification.”

Around midday Wednesday, the attackers entered the Inland Regional Center for the developmentally disabled in San Bernardino and opened fire on attendees at a holiday party for county workers, killing 14 and injuring 17. The couple fled the scene after the massacre and reportedly left pipe bombs behind. Farook was born in Illinois, while Malik was born in Pakistan and lived in Saudi Arabia before coming to the U.S. when she married Farook.

President Barack Obama said on Thursday it was possible that the attack was terrorist-related or work-related, and authorities were still investigating.

Speaking at a press conference organized by CAIR on Wednesday, Dr. Muzammil Siddiqi, religious director of the Islamic Society of Orange County, spoke of his organization’s “sadness and sorrow at what happened in San Bernardino” and asked the public not to implicate Islam or Muslims in the attack.

“I want to condemn this action, this action of violence,” said Siddiqi. “We have condemned all violence, everywhere, because human life is precious, and we respect and honor the human life.”

He added, “Our faith is against this type of behavior.”

Also speaking during the CAIR press conference, Ayloush said the group “unequivocally” condemns shooting and stands “in solidarity with fellow Americans as we offer our heartfelt prayers and condolences to the injured, to the families of those who have been killed.”

He continued, “We stand in solidarity in repudiating any possible ideology or mindset that could have let to such a horrific act. There’s absolutely nothing that could justify [it]. We stand in mourning, in sadness for what happened, and we pray for the quick recovery of those who were injured.”

In his interview with NPR on Thursday, Ayloush and said “it’s hard to tell” how religious the two suspects were, but their families are “moderately religious” and take their religion seriously.

Farhan Khan, Farook’s brother-in-law, also spoke at the CAIR press conference and said he “cannot express how sad I am for what happened today.”

“I am in shock that something like this can happen,” he said. The last time he spoke to Farook was a week ago, he said, adding that he has “absolutely no idea” why his brother-in-law would carry out a mass shooting.

The Ahmadiyya Muslim Community released a statement on Wednesday that called the shooting “senseless” and “tragic.”

“We extend our condolences to the victims and their families,” said Nasim Rehmatullah, senior vice president of Ahmadiyya Muslim Community USA. “The Koran teaches us the killing of an innocent is like the destruction of mankind. Humanity was destroyed far too many times today.”