The race to figure out who is behind the string of homemade explosives sent to prominent critics of President Trump across five states and Washington, D.C. is intensifying as officials warn there could be more to come. According to the FBI, at least three of the packages contained pipe bombs. Former FBI profiler Mary Ellen O'Toole said there's an "arrogance" to the coordinated attack that could offer clues about who did it.

"If they're intentionally designed not to explode but to create fear and panic, then we can possibly expect to see an escalation if there's another batch of bombs that come out. This suggests to me that this is someone that really planned this out quite well, so we should not assume that mistakes that we see in the posting of the packages are a mistake but may be done purposefully. There's also an arrogance about these bombings," she said.

None of the crude devices discovered so far have detonated and their functionality remains unclear. A photo obtained by CBS News also shows that the package found in the CNN mailroom, which was addressed to former CIA Director John Brennan, misspelled Brennan's name and the last name of former DNC chair Debbie Wasserman Schultz, who is listed as the return address. According to O'Toole, there's a possibility these mistakes were intentional.

Intended recipients of the packages include former President Obama, former Vice President Joe Biden, former Secretary of State Hillary Clinton, former CIA Director John Brennan, former Attorney General Eric Holder and liberal philanthropist George Soros. On Thursday morning, another possible bomb was found at actor Robert De Niro's at New York production house.

This photo obtained by CBS News shows what is described as the explosive device sent to former CIA Director John Brennan at CNN's New York City offices.

"This is someone who is creating a great deal of fear and panic in New York and in the D.C. area and he's enjoying that. My sense is that the sense of power and control and omnipotence that he's getting out of really being the center of attention now throughout the country is probably like a narcotic for him. So that can play a part in how these bombs may start to evolve or how this series of attacks may start to evolve," O'Toole said on "CBS This Morning" Thursday.

Based on the type of device and the packaging, O'Toole said there's a lot of potential for trace evidence.

"When someone is making a device, they turn the wires a certain way, they may put a piece of the device in their mouth while they're working with their hands and then that piece comes out of their mouth, we've got DNA. So people are not that sophisticated to what could be used to obtain their identity. There's a wealth of information here and this offender has taken a lot of risk. He can't go back and change that now," O'Toole said.

Though she repeatedly used the pronoun "he" when referring to the bomber, O'Toole clarified she doesn't have any evidence to suggest the suspect is a male but that anecdotally serial bombers tend to be male.

CBS News senior national security analyst Fran Townsend, who was homeland security and counterterrorism adviser for President George W. Bush, told "CBS This Morning" that so far, there's no indication the string of bombs represents an overseas threat.

"Although they're calling this terrorism... I think the operating assumption, from investigators that I've spoken to, is it is a homegrown threat," Townsend said.