Well, I searched for this information. I found that 95% number several places, but it all seems to come from this article;
"In Los Angeles, 95 percent of all outstanding warrants for homicide (which total 1,200 to 1,500) target illegal aliens. Up to two-thirds of all fugitive felony warrants (17,000) are for illegal aliens."
Link
However, she cites no source for this statistic(also, it is
outstanding murder warrants, unsurprising if you think about the fact that it's much harder to track an illegal immigrant than a legitimate citizen). I've found it used in various other webpages, lifted whole from the article, but still no source (not even to the original article in some cases). I would be interested to see where Heather MacDonald got the number, so I emailed the City Journal. I'll let you know if I get a response.