There have been more than 370 suspicious package calls as of 8:30 a.m. today, since the first explosion on March 2, according to police.
The calls followed three package bombs that detonated at different residences in the city, killing two and injuring two others.
The three bombings took place 11 days apart -- March 2 and then two this Monday -- but police have said that they believe they’re related.
Authorities have advised residents to exert caution and call authorities if they see any unexpected or suspicious packages near their homes.
Police said they had received 265 calls Tuesday afternoon, followed by an additional 108 calls between then and this morning.
Federal and local investigators have been working nonstop to find the suspect or suspects, Austin Police Chief Brian Manley told ABC News.
"We are definitely dealing with a suspect or suspects who has some level of skill in making these types of devices," Manley said Tuesday.
"The fact they have not only been able to build these bombs, but then travel with them to the target location without them exploding either during construction or during deployment, shows that they do have a certain level of sophistication and they know what they are doing," he said.