The claim I wish to examine is from dcwhispers.com,
Case in point—the number of deaths, assaults, and sex crimes, including human trafficking, taking place on America’s southern border dwarfs by many times over the number of deaths attributed to mass shootings. And yet it’s mass shootings that the media covers 24/7 and tens of thousands march against.
Reading the entire article, I distill the claim to be
An America without illegal immigrants would have far fewer murders than an America without mass shootings
Please note, this is my interpretation of what the article is really saying; but this is the specific claim I want to check.
Sources from the claim
The article claims there are 1135 mass shooting deaths since 1966, uncited. I can also find this identical number from the Washington Post (accessed 1/10/19). This is about 22 homicides per year since 1966. Alternately, in 2017 and 2018, the same WaPo site lists 185 shooting deaths in 16 incidents, so you could use the higher recent rate of mass shootings deaths.
For the criminal alien homicides, the article quotes Fox News:
Now, in the past two years alone, criminal aliens have been responsible for approximately -- look at this number -- 235,000 violations of the law, including 4,000 homicides, 30,000 sex crimes and -- get this -- over 100,000 violent assaults.
While uncited, I believe the homicide numbers come from these 2017 and 2018 reports from US Immigration and Customs Enforcement (ICE). These reports show that the persons arrested by ICE in 2017 were collectively charged 355 times and convicted 1531 times of homicide, presumably for all time prior to the report. The 2018 numbers were 387 charges and 1641 convictions of homicide. Sum all four of these numbers, and we get 3914; which is where I believe the 4000 figure from Fox New and the original claim comes from.
The claim's misinterpretation of source
However, this number is not a valid comparison to the number of mass shooting deaths. First, these murders occur over a period of more than the two years covered. Second, there is this note within the 2017 report saying:
The criminality displayed includes all criminal charges and convictions for FY2017 ERO administrative arrests entered into ICE’s system of record at the time of the data run. An alien may have more than one criminal charge or criminal conviction in a fiscal year, and all relevant charges and convictions for each arrest are included. As such, the total number of criminal charges and convictions is greater than the total number of aliens administratively arrested.
Some murders charges and convictions are double counted (or more). Given this, it seems obvious that someone subject to ICE administrative enforcement action in both 2017 and 2018 would also be double counted. So, if all illegal immigrants did not exist in 2017 and 2018, the number of prevented murders in that time period would be significantly less than 4000.
Is there some other way to compare the average number of mass shooting deaths per year to the number of murders committed by illegal immigrants per year? Do illegal immigrants commit more murders per year than mass shooters?