Factbox: Hate crimes in the United States

(Reuters) - U.S. law enforcement authorities were investigating the Wednesday night slayings of nine people by a white gunman at a historic black church in Charleston, South Carolina, as a hate crime.

While the death toll made the attack one of the worst in recent years in the United States, hate crime is far from uncommon, according to experts.

There have been 4,120 reported hate crimes across the country, including 56 murders, from 2003 until 2015, according to the Southern Poverty Law Center, a Montgomery, Alabama-based advocacy group. (Graphic on hate crime in the United States, http://link.reuters.com/dyf94w)

The Federal Bureau of Investigation says a hate crime is "a traditional offense like murder, arson, or vandalism with an added element of bias." Under federal law, a hate crime is defined as a "criminal offense against a person or property motivated in whole or in part by an offender’s bias against a race, religion, disability, ethnic origin or sexual orientation," the FBI says on its website.

The Charleston shootings brought back memories of the civil rights-era 1963 bombing of a Baptist Church in Birmingham, Alabama that killed four black girls.

Following is a list of some of the more serious or notorious hate crimes:

Feb. 10, 2015: Three young Muslims were gunned down at an apartment near the University of North Carolina campus in Chapel Hill. A neighbor, Craig Stephen Hicks, is arrested. The killings, which are being investigated as a possible hate crime, sparked an outcry overseas.

April 2014: Three people were fatally shot to death outside two Jewish centers in Overland Park, Kansas. Frazier Glenn Cross, a former senior Ku Klux Klan member who had expressed a hatred for Jews, has pleaded not guilty to murder charges. However, all three victims were Christians.

August 2012: White supremacist Wade Michael Page walked into a Sikh temple in Oak Creek, Wisconsin, and fatally shot six worshippers. Page, who wounded four others, including a policeman, was shot by police in a temple parking lot before killing himself.

February 2011: A group of white men ambushed and beat James Craig Anderson, a 47-year-old black man, in Jackson, Mississippi. Anderson died after one of the men, Deryl Dedmon, ran him over with his truck. Dedmon drew a 50-year federal prison sentence. In all, 10 people were convicted in the crime.

September 2001: Arizona gas station owner Balbir Singh Sodhi, a Sikh, was shot to death by Frank Silva Roque, who mistook Sodhi for a Muslim and was seeking revenge for the Sept. 11, 2001 attacks on the United States. Roque was sentenced to death but was later resentenced to life imprisonment.

October 1998: Matthew Shepard, a gay University of Wyoming student, is severely beaten and left to die tied to a fence outside Laramie, Wyoming. The 21-year-old dies five days later. Russell Henderson pleaded guilty to murder, and Aaron McKinney was convicted of murder.

June 1998: James Byrd Jr., a black man, is killed by being dragged behind a truck near Jasper, Texas. White supremacist Lawrence Russell Brewer is executed in 2011 for the crime. Two others were charged in the kidnapping and slaying.

March 1981: Michael Donald, 19, a black man, is kidnapped and murdered by two Ku Klux Klan members in Mobile, Alabama. His body is left hanging from a tree, leading some to characterize the killing as the last recorded lynching in the United States.

April 1968: The Rev. Martin Luther King Jr. is shot down by James Earl Ray while standing on a motel balcony in Memphis, Tennessee. The assassination of the revered civil rights leader sparks rioting in cities across the United States. Ray, a white man who was prejudiced against blacks, died in prison in 1998.

August 1955: Emmett Till is beaten, shot and mutilated in Money, Mississippi four days after the black 14-year-old reportedly flirted with a white woman. The woman's husband, Roy Bryant, and J.W. Milan were acquitted of the crime, which helped spark the modern civil rights movement.

(Compiled by Jonathan Oatis; Editing by James Dalgleish and Lisa Shumaker)