So why would law enforcement officials decide not to report to federal authorities persons suspected of?

This is common in too many states unfortunately, Maryland is a sanctuary state and is fighting now to appeal this. I think the police should hand every known illegal or suspected illegal straight over to ICE instead of just a list of names of people who have committed just felonies. It is sad too, because since Virginia and Penn. have started deporting and getting strict on illegals, they have benn swarming into MD, especially since they use to be able to get drivers license, thankfully Maryland has stopped this.