Everyone knows this. No one wants to talk about it. Because once you want to talk about it, then you need to look at the hard numbers and the difficult issues. Such as:

Black Americans have an average IQ of 85 https://www1.udel.edu/educ/gottfredson/30years/Rushton-Jensen30years.pdf

Chronic adult criminals have an average IQ of 85 https://archive.is/iRPsZ#selection-131.67-131.126

U.S. data: At each poverty concentration level, the violent crime rate is substantially higher in black than in white census tracts. https://www.realclearpolicy.com/articles/2017/02/16/race_and_rising_violent_crime.html

IQ and self-reported lifetime violence accounts for racial disparity in criminal justice processing https://www.sciencedirect.com/science/article/pii/S0191886913000470

In 1959, the American Association of Mental Retardation set the threshold of mental retardation at <85 http://archive.is/1mNdz#selection-311.2-311.69

The white-black gap in SAT scores, a proxy for IQ, is increasing https://archive.is/uSx7u

Black women are about 2X more likely than white women to be jail. Black men are about 6X more likely than white men to be in jail. http://thealternativehypothesis.org/index.php/2016/09/25/child-abuse-and-racial-differences-in-crime-and-iq/

The 2-repeat allele of the MAOA gene confers an increased risk for shooting and stabbing behaviors https://pubmed.ncbi.nlm.nih.gov/24326626/ From the abstract: The current study builds on this research and examines the association between the 2-repeat allele and shooting and stabbing behaviors in a sample of males drawn from the National Longitudinal Study of Adolescent Health. Analyses revealed that African-American males who carry the 2-repeat allele are significantly more likely than all other genotypes to engage in shooting and stabbing behaviors and to report having multiple shooting and stabbing victims.

And these numbers are just scratching the surface. The 13/50 number is infamous, but when you think about it, it's really closer to 6/50 (or 6/45).