The acquittal of George Zimmerman, a white Hispanic, in the shooting death of Trayvon Martin, a black teenager, has prompted commentary from the left and right about race and murder statistics.

We saw this statistic repeated multiple times by conservatives on Twitter after the July 13 verdict: "In the 513 days between Trayvon dying, and today’s verdict, 11,106 African-Americans have been murdered by other African-Americans."

We will leave it up to others to interpret the relevance of such statistics in the Zimmerman trial or other cases. Our role here as fact-checkers is to examine the numbers and their context.

A quick note on the case before we turn to the numbers: Hispanic is an ethnicity -- someone can be Hispanic and white, as in Zimmerman’s case -- or Hispanic and black. The crime data we reviewed generally focused on whites and blacks, though it sometimes included a generic "other" category.

Martin, 17, was unarmed when he got into a scuffle with Zimmerman in Sanford, Fla., on Feb. 26, 2012. A jury acquitted Zimmerman, a neighborhood watch volunteer whose lawyer argued self-defense, of second-degree murder and manslaughter. (Read our fact-checks that relate to the case and Florida’s "stand your ground" law.)

Statistic about blacks killed during course of Trayvon case

We found the claim about murders on the conservative soopermexican blog; it appears to have originated there. His blog walks readers through the math on getting to 11,106 deaths in 513 days. (We counted 503 days, not 513, but that’s a tiny quibble.)

The blogger, citing an earlier blog post and The Blaze, stated that there were 8,000 to 9,000 African-Americans killed each year -- 93 percent of them by African-Americans.

The numbers came from a 2007 U.S. Bureau of Justice Statistics report, which stated that blacks were victims of 7,999 homicides in 2005 and said that 93 percent were killed by people who shared their race. (It wasn’t clear to us where the blogger’s 9,000 figure came from.)

Using the number 8,500, that translated to 21.65 blacks murdered each day by other blacks. So the blogger came up with a mathematical formula: 21.65 times 513 days=11,106. That 8,500 figure seems high, though, especially if we look at more recent figures. The FBI reported for 2011 that 6,329 black people were murdered, for example.

The blog post makes it sound as if the black-on-black murder rate is particularly significant, but we found similar high percentages for whites.

The report also stated that 85 percent of white victims in single-victim and single-offender homicides were murdered by someone of their race. So that means the majority of black and white people are murdered by someone of their own race. In 2005, there were 8,017 white homicide victims. (Editor's note, May 21, 2015: We have since collected statistics on additional years and published those findings in a more recent report.)

The race victim/offender data isn’t shown for every case: It is only shown in the cases in which the race was known (some murders are never solved) and in cases involving a single victim and defendant.

We sent a summary of our findings to the soopermexican blogger.

"I think your criticism of the number I arrived at has some merit," he wrote in an email. "I should have made it more clear that is the best extrapolation from the numbers that are available. While the FBI stats don't include all known cases, I don't see why the cases where race stats are known shouldn't be representative of the entire class of murders. Yes, it's true that murder rates have come down generally, which I'm pretty sure applies to all race/ethnic classes."

As for white-on-white homicides also representing a high percentage, he said the point he was trying to make is that it’s wrong to suggest that "white racism is killing blacks disproportionately."

What homicide-race stats show about our relationships

So statistics show that most murders in which the race can be measured are intraracial. We wanted to know why.

We interviewed Professor David M. Kennedy, director of the Center for Crime Prevention and Control at John Jay College of Criminal Justice in New York City.

"Homicides overwhelmingly happen among people who know each other," he said. "There are relatively few absolutely straight-up stranger homicides. Homicide is a phenomenon of social networks. ... Most peoples’ relationships are primarily with someone of their own race or ethnicity. As long as anybody has studied homicide, this has been the pattern." (See the historical data.)

Writer Jamelle Bouie in The Daily Beast wrote a response to conservatives who have been trying to shift the conversation to black-on-black crime while ignoring that the same shared racial identity holds true for white-on-white crime, too.

Bouie wrote that what is missing from the conversation about crime is that "it’s driven by opportunism and proximity; If African-Americans are more likely to be robbed, or injured, or killed by other African-Americans, it’s because they tend to live in the same neighborhoods as each other. Residential statistics bear this out (PDF); blacks are still more likely to live near each other or other minority groups than they are to whites. And of course, the reverse holds as well—whites are much more likely to live near other whites than they are to minorities and African-Americans in particular."

Our ruling

In response to the Zimmerman case, social media repeated this claim: "In the 513 days between Trayvon dying, and today’s verdict, 11,106 African-Americans have been murdered by other African-Americans."

Some who are citing this statistic are using it to portray race as an overemphasized point in the Zimmerman trial. We’re not evaluating that opinion; we’re fact-checking the math based on the available data.

The number sounds extremely precise, but it's actually something of a rough guess based on back-of-the envelope math. No one actually knows how many African-Americans were murdered by other African-Americans in that time frame, and the numbers cited are actually an extrapolation of murder statistics for 2005. More current figures from 2011 show fewer deaths. So the specific numbers are not literally accurate.

Also, this claim lacks important context. Yes, it’s true that the majority of black murder victims are murdered by blacks, but the same holds true for whites: Most whites are murdered by whites. And in both cases, this race statistic is not available for all murders, but only ones where the race of both perpetrator and victim can be determined.

The claim contains an element of truth, but it's not fully accurate. We rate this claim Mostly False.