WASHINGTON (AP) — A North Texas police chief says a lack of solid data on hate crimes is one of the greatest barriers to fighting the problem.

Will Johnson, the police chief in Arlington, Texas, told a congressional panel that both law enforcement agencies and victims need better training and education on the importance of collecting and reporting hate crime figures.

Johnson spoke before the Senate Judiciary Committee's hearing on religious hate crimes. He says more agencies need to provide their crime data to the FBI, which keeps figures that are undercount because reporting is voluntary.

Johnson also says law enforcement officials struggle with when to classify an offense as a hate crime because motive can be tricky to prove. And building relationships among officers and communities can help improve information-sharing.