Police have sought the help of FBI's hate-crime investigators to probe the December killing of two Sikh brothers who ran a restaurant in California.
Ravinder Kalsi, 30, and his brother, Paramjit, 42, were shot down just when they were closing their Sahib Indian Restaurant in Richmond, San Francisco, on the evening of Dec 27.
The FBI has been asked to look into the hate crime angle because the restaurant was not robbed and police are still groping for a motive.
"The surveillance camera footage of the suspects has generated a lot of calls and tips," detective Mitch Peixoto said. "But so far, nothing has panned out."
Richmond police has offered a reward of $10,000 for information leading to the arrest and conviction of the killers. An anonymous benefactor has offered an additional $10,000.
The Kalsi brothers were from Patiala in Punjab and had worked their way up, acquiring the restaurant in 2002.