WEST HAVEN - So, what is it that investigators are looking for in trying to determine who is responsible for sending the increasing number of suspicious packages?
Kenneth E. Gray, Jr., a retired Special Agent, in the FBI's New Haven Field Office, has worked a high-profile mail bomb case. So, he's keeping a close eye on these developments.
The first suspicious package that came to light this week was one delivered to the New York residence of business magnate and political activist George Soros. But, it did not come via mail.
"So, that indicates that the person, the bomber, may be local here, maybe somewhere in the northeast," said Gray, who is now a lecturer at the University of New Haven.
One thing that caught Gray'sa eye about the envelopes: They each contain quite a few postage stamps.
"That means that the person probably did not go up to the window in the post office and mail those packages," he said.
And each envelope will be carefully examined, inside and out.
"There might be DNA on the tape itself," said Gray. "Might be DNA on the stamps themselves."
The fact that some of these packages were sent to past president would trigger immediate investigations into people, who have made threats against them in the past.
As for other vetting?
"People who have done bombings in the past or delivered packages in the past - suspicious packages - that would be of interest, too," he said.
Gray said the packages contained what appeared to be pipe bombs. But, he added, there has been no information revealed about the fusing system.
"You see some wires coming out of it. They look like fake bombs," Gray says. "They don’t really look to me like actual bombs themselves, but you still have to treat it as a real bomb."
25-years ago, then Special Agent Gray was one of two New Haven agents to investigate what became known as the Unabomber mail bomb campaign, which injured Yale professor, David Gelernter.
"When he came out of surgery I went in and interviewed him immediately afterwords and did another number of interviews with him," said Gray.
The Unabomber mail bomb campaign, which killed three people and injured 23, started in the late 1970's and continued until Ted Kaczynski was caught in 1996.