you a great fourth of July. Thanks goodness it passed without the kind of incident that had officials so worried. Cities and towns on high alert for a possible terror attack. Here in New York, 7,000... See More
you a great fourth of July. Thanks goodness it passed without the kind of incident that had officials so worried. Cities and towns on high alert for a possible terror attack. Here in New York, 7,000 police officers deployed to protect the fireworks. ABC's senior justice correspondent Pierre Thomas has been tracking the threat, and Pierre so far so good. Reporter: Good morning, George. That's right, law enforcement is breathing a sigh of relief that we made it through Independence day without any attack on U.S. Soil. High security throughout the country. Specifically concerned about Isis and the threat of lone wolves. Unfortunately, the unprecedented social media campaign by Isis which is happening now as we speak is urging its followers to carry out attacks, including here in the U.S. We're also at the one-year anniversary of the formation of the so-called islamic state. A threat that authorities are paying attention to, right now we're in the islamic holy month of Ramadan, which does not end until July 17th. Called on followers to make Ramadan, quote, a month of disasters for those infidels. Followers are listening. This will be a long, uneasy summer, George. They'll keep trying. Pierre, you also cover homeland security and immigration. Let me ask you about that hour riffic case out of San Francisco, Kate Steinle was killed by an illegal immigrant, deported five times, a lot of people wondering, how could someone like that be in the United States be free? Reporter: George, what a tragic case and this may be a classic example that bureaucracy can kill. Fed ram immigration officials are pointing a finger squarely at local authorities. They say this criminal as you said, deported five times never should have been released by the city. They say Francisco Sanchez was handed over to the city because of an outstanding drug charge there. Prior to that he had been in prison for being a repeat illegal immigration offender. A specific request to be notified once the local case was resolved, but that did not happen. Once the drug charges were dropped, Mr. Sanchez was simply free to go. San Francisco is a safe haven city that does not detain undocumented immigrants. George, who is right is the subject for debate. The feds said they did everything by the book. Should the locals simply notified the feds when the case ended? Or should fed ram immigration officials had been closely monitoring the case?
This transcript has been automatically generated and may not be 100% accurate.