Out here in California, San Francisco and Los Angeles both pride themselves as "sanctuary cities". That means they practically welcome illegal aliens, More specifically, they don't cooperate with ICE when it comes to the illegal aliens that go through their respective justice systems. That means that illegal alien who get arrested for crimes often go through the local justice system and when they are released from jail, ICE isn't notified.
This was brought home with great force in recent years when a high school football star, Jamiel Shaw, was shot down and killed on a sidewalk near his home by an illegal alien gang member who had just been released from jail with no notice to ICE.
The same year (2008) , another illegal alien gang member (MS 13) just out of jail in San Francisco shot and killed a man and his two sons in a road rage incident.
You would think these cities would learn, but they don't. Now we have another innocent person shot to death in San Francisco by an illegal alien who, in this case, has been deported five times.
I don't know the details about this latest killer's (Francisco Sanchez) 5 deportations, but the last one was in 2009, and he was recently released from jail even though ICE had requested he be turned over to them. A federal hold means that the locals don't simply release prisoners on the street, but turn them over to the feds when they are finished with them. To be fair, the locals don't want to hold prisoners any longer than their local charges warrant for fear of lawsuits, so it behooves the feds to be there on time when the person is released.
Here is the trick: ICE literally has to determine on their own when a person is going to be released and be there at the jail to grab them as they leave. The way the system should work is that ICE places a hold and coordinates with the locals to know when a release is to be made so they can take custody. It's a simple procedure, but it is clear that the locals are not fully cooperating. As I understand it, only in cases of prisoners convicted of serious felonies will the local notify ICE and inform them when the prisoner will be released. So in LA and San Francisco, we have illegal alien criminals getting out of local jails and nobody tells ICE. Now we see the result.
By the way, one of the public figures involved in this mess is Kamala Harris, former San Francisco DA and current California attorney general. She is now running for the US Senate seat being vacated by Barbara Boxer and is a favorite to win the Democratic nomination. Since California is literally devoid of Republicans that means she will probably be our next US Senator.