The largest civil rights group for Muslims in the U.S. has requested a hate crimes investigation in Texas after an apparent road rage shooting left a man dead last weekend. The Council on American-Islamic Relations said Monday it told the Federal Bureau of Investigation that a hate crimes probe was necessary because of anti-Muslim statements allegedly made by a gunman charged in last Friday's shooting death of 42-year-old victim Zaid Abu Naim.

Robert Craig Klimek, 43, has been charged with aggravated assault with a deadly weapon in Naim’s death. However, Houston police spokeswoman Jodi Silva described the shooting as one of road rage “at its heart.” A CAIR representative in Houston said witnesses have attested to Klimek’s alleged slur against Naim: “Go back to Islam.”

"We urge state and federal law enforcement authorities to investigate a possible bias motive for this shooting and to bring appropriate charges if that motive is proven," said Mustafaa Carroll, the executive director of CAIR's Houston office. "We have seen too many cases of anti-Muslim hate, threats and violence recently nationwide to ignore the possibility that Islamophobia led to this terrible incident."

Authorities say the shooting grew out of a dispute over who had the right of way at a four-way stop, according to the Houston Chronicle. “Words were exchanged," Silva said, "and the victim went to confront the other driver." Police did not say what prompted Klimek to fire, but family members, witnesses and CAIR claimed the shooting was unjustified and was carried out “executive style.” Naim, who is of Palestinian heritage, died Sunday in a Houston hospital.

"My brother was a good person," said Eyad Naim, 38. "A lesson should be taught about this. All that I want is justice for my brother.”

Craig Seldin, an attorney for Klimek, who is free on $50,000 bail, denied accusations that the shooting was motivated by hate. "This had nothing to do with hate crime," Seldin said Monday after Klimek appeared in court. “There was a disagreement over the way each driver was handling a traffic situation. We're asserting a self-defense defense."