I suspect a family member - simply because most murders are family related, in all religious and ethnic groups. Always the most likely cause.
A family member, or someone well-known to the family would be most likely, especially since it's happened in this family before:
She (a cousin) said this is the second time a family member has been shot and killed in Fremont. She wouldn't provide details, but Fazayun Ansari confirmed that a relative, Afghan community leader Rahim Ansari, 34, of Union City was shot and killed in January 2002 inside his business, Pamir Travel, in the heart of Fremont's close-knit Little Kabul neighborhood, the nation's largest Afghan community.
The suspected gunman, upset over a spurned romance, killed Ansari and wounded his brother-in-law, Zabiullah Ansari, 42, of Fremont, police said.