By Tiffany Chan

BOSTON (CBS) – The manhunt is on for a serial bomb maker who mailed explosive devices across the country. The targets were top Democrats, including former President Barack Obama and the Clintons.

The FBI will have to trace the packages back and rely heavily on forensics to catch the person responsible.

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“This is not an easy thing to do,” said WBZ security analyst Ed Davis.

Difficult, because it will likely take a lot of time and manpower to identify the bomb mailer. Davis says FBI investigators will begin with the evidence they have, six brown manila envelopes containing what appear to be homemade pipe bombs.

WBZ security analyst Ed Davis (WBZ-TV)

“They’ll look for DNA, they’ll look for fingerprints,” Davis said.

Davis, who led the investigation into the Boston Marathon bombings, says authorities will now trace the packages back and review surveillance video within a 10-block radius of the mailboxes.

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“It’s hard to build all of this stuff – to compile all this equipment that’s needed, to put the stuff together and to send articles out like that without leaving some trace,” Davis said. “And I think that that’s really the downfall of most of the individuals involved here.”

Pipe bomb mailed to CNN (Image from CNN)

The suspect has already left behind some clues. The suspicious packages were mailed to top Democratic figures and news outlets, suggesting the motive was likely political.

U.S. Senator Ed Markey (D-Mass) says told WBZ it’s a cause for concern.

“I think journalists and politicians in this environment should be especially careful,” Sen. Markey said. “It’s a dangerous period of time.”

Detectives are ultimately looking for that big break, any DNA, any hair or fingerprints inside of the packages that will help them narrow in on a suspect.

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“If you look at all of the incidents that have occurred, most of them have ultimately been solved and I expect that will happen here,” Davis said.

Tiffany Chan