Zafar Ahmad Abdul Ghani, a Rohingya Muslim refugee and activist who fled persecution and ethnic strife in Myanmar, has called Malaysia home for nearly three decades.

Now, Malaysia is more like a prison for him and his family.

Zafar, 51, has not left his home on the outskirts of Kuala Lumpur for nearly a year, after misinformation spread online that he had demanded Malaysian citizenship, triggering a wave of hate speech and death threats against him and his family...