http://www.city-journal.org/html/14_1_the_illegal_alien.html
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.
A confidential California Department of Justice study reported in 1995 that 60 percent of the 20,000-strong 18th Street Gang in southern California are illegal aliens.
Alexandria, VA: Speaking out for the first time on the question of immigration enforcement, the International Association of Chiefs of Police (IACP) today announced its opposition to the Clear Law Enforcement For Criminal Alien Removal (CLEAR) Act and urged Congress to proceed with caution when considering measures that would compel local and state law enforcement agencies to enforce federal immigration laws. The IACP took this action after a careful review of the impact that enforcing immigration law could have on state, tribal and local law enforcement and the communities they serve.The IACP opposes any plan that would coerce local and state law enforcement agencies to enforce federal immigration laws without their approval, said IACP President Joseph Estey, Chief of the Hartford, Vermont Police Department. Many leaders in the law enforcement community have serious concerns about the chilling effect any measure of this nature would have on legal and illegal aliens reporting criminal activity or assisting police in criminal investigations. This lack of cooperation could diminish the ability of law enforcement agencies to police effectively their communities and protect the public they serve. {blah, blah, blah}...
And speaking of LA, maybe you should have read the story preceding your statistics on that website you linked to:
The LAPDs ban on immigration enforcement mirrors bans in immigrant-saturated cities around the country, from New York and Chicago to San Diego, Austin, and Houston. These sanctuary policies generally prohibit city employees, including the cops, from reporting immigration violations to federal authorities.The enforcement is being thwarted at the local level.