Austin remains on edge following yet another explosion in the early hours of Tuesday morning.
President Trump spoke about the Texas bombings Tuesday, calling the "serial bomber" a "very, very sick individual."
The urgency intensified after a fifth bomb in the string of explosions that began March 2 went off at a FedEx distribution center outside San Antonio in the city of Schertz.
The package was reportedly on its way to an address 80 miles away in Austin. Like the other packages, the FedEx bomb contained nails, bolts, and shrapnel, indicating it was designed to inflict maximum injury.
No one was hurt in the FedEx explosion and officials say it was on an automated conveyor belt when it went off.
Retired FBI special agent Bobby Chacon, who serves an expert consultant on TV’s Criminal Minds, told Inside Edition that he doubts the bomber "is an amateur learning off of YouTube."
He added: "If you look at the serial bombings that have happened before, there is that certain pattern — male, white, upper middle class, above average intelligence. I think that to go undetected in an activity like this requires a bit of isolation from social groups, and friends and family."
On Monday, cops made a plea for the bomber to speak with officials and Chacon weighed in on their tactic.
"The bomber, I believe, wants to talk," he said. "He wants a message out there. I think that some of these events, initially in this pattern, are designed to get attention to people so that when he ultimately has the platform to make that statement, he has everyone’s attention."
The FBI and the Bureau of Alcohol, Tobacco, Firearms and Explosives are assisting local police forces with the investigation as to who the "serial bomber" is. Authorities say the bomber remains at large and have warned that the devices appear to be getting more sophisticated.
Austin resident Trevor Ingram, 26, has been arrested and charged with allegedly emailing a bomb threat that resulted in the cancellation of a concert by The Roots over the weekend at the SXSW festival.
Police say Ingram has been ruled out as the bomber.