The man charged over Friday’s twin mosque attacks in the New Zealand city of Christchurch is believed to have acted alone, police say.
Australian Brenton Tarrant, 28, a self-described white supremacist, live-streamed the attack on Facebook.
Three others arrested afterwards are not believed to have been involved, Police Commissioner Mike Bush said, but added that he could not be conclusive.
Fifty people were killed and 50 injured in what is New Zealand’s worst attack.
Some 34 people remain in hospital receiving treatment for injuries ranging from severe gunshot wounds to “relatively superficial soft tissue injuries”, authorities said.