FBI nabbed bomb suspect with DNA clues

In the hours before his arrest, as federal authorities zeroed in and secretly accumulated evidence, Cesar Sayoc was in his element: spinning classic and Top 40 hits in a nightclub where he'd found work as a DJ.
As he entertained patrons from a dimly lit booth overlooking a stage at the Ultra Gentlemen's Club, where Halloween decorations hung in anticipation of a costume party, he could not have known that investigators that very evening were capitalising on his own mistakes to build a case against him.
He almost certainly had no idea that lab technicians had linked DNA on two pipe bomb packages he was accused of sending to prominent Democrats to a sample previously collected by Florida state authorities. Or that a fingerprint match had turned up on a separate mailing the authorities say he sent.
And he was probably unaware that investigators scouring his social media accounts had found the same spelling mistakes on his online posts - 'Hilary' Clinton, Debbie Wasserman 'Shultz' - as on the mailings he'd soon be charged with sending.
In the end, prosecutors who charged Sayoc with five federal crimes say the fervent President Donald Trump supporter unwittingly left behind a wealth of clues, affording them a critical break in a coast-to-coast investigation into pipe bomb mailings that spread fear of election-season violence. The bubble-wrapped manila envelopes, addressed to Democrats such as Barack Obama and Hillary Clinton and intercepted from Delaware to California, held vital forensic evidence that investigators say they leveraged to arrest Sayoc four days after the investigation started. 
"Criminals make mistakes so the more opportunities that law enforcement has to detect them, the greater chance they're going to be able to act on that, and that appears to be what happened here," said former Justice Department Aloke Chakravarty. 
But It wasn't always clear that such a break would come, at least not on Monday when the first package arrived: a pipe bomb delivered via mail to an estate in Bedford, belonging to billionaire George Soros. That same day, Sayoc, still under the radar of law enforcement, retweeted a post saying, "The world is waking up to the horrors of George Soros." 
Additional packages followed, delivered the next day for Clinton and Obama and after that to the cable network CNN, former Attorney General Eric Holder, former vice-president Joe Biden and other Democratic targets of conservative ire. Each additional delivery created more unease. But together they also provided more leads for the FBI, which mined each pipe bomb for clues at a laboratory in Quantico, Virginia. 
As the packages rolled in, technicians hit a breakthrough: a fingerprint and DNA left on a package sent to Rep. Maxine Waters, a California Democrat and one of the intended pipe bomb recipients, and DNA on a piece of pipe bomb intended for Obama. The FBI said it had identified no other possible matches on the evidence it had examined.