AUSTIN, Tex. — A growing sense of fear and panic spread across Texas’ capital on Monday after the latest bombing attack this month. The authorities say, the blast injured two people in Austin on Sunday. The authorities confirmed the makeshift bomb appeared to be connected to three earlier bombings, but the bomb demonstrated a “higher level of organization and sophistication” with the use of an invisible tripwire triggering device, according to the Associated Press.

The three bombings that happened earlier this month were involved with packages that were left on doorsteps and blew up when moved or opened, killing two people and injuring two others, according to the Associated Press.

Police Chief Brian Manley said, “We are clearly dealing with what we believe to be a serial bomber at this point,” he told reporters at a press conference in Travis Country, where the latest bombing occurred, according to the New York Times. He cited connections among the four bombs that has happened in Austin, according to the Associated Press.

Austin on edge: perpetrator sparked fear in the city

The latest attack by the perpetrator occurred in a different part of the city Austin, and both of the people who were wounded are white, while the victims in the earlier attacks of this month were black or Hispanic, according to the Associated Press. Residents in Austin have been asked by authorities to remain indoors through the early part of the day and be vigilant for suspicious packages, like boxes or backpacks, according to the Associated Press.

Thad Holt, 76 who lives in the gated condominium community of 5000 Mission Oaks, a few miles from Sunday’s bomb attack, said an occasional car break-in is the kind of crime most typical in the neighborhood, in an interview with the New York Times. He said, “it’s too close for comfort,” Mr. Holt said. “Fear of this recent attack has put everyone in the whole town on edge.”

Large investigation

The FBI and Police Chief, Brian Manley have not found a motive of bombings from the Austin serial bomber.

Police Chief, Brian Manley quoted, “Is this terrorism? Is this hate-crime?” He asked. He said investigators will “have to figure out if we see a specific reasoning behind this crime, or something major that will lead us along with our federal partners to make that decision,” said Mr. Manley in an interview with the New York Times.

Hundreds of agents from the FBI, and the U.S. Bureau of Alcohol, Tobacco and Firearms along with Austin police department have joined the investigation to look into the latest attack.

The FBI behavioral analysts from Quantico, VA who are helping with the investigation were trying to build a profile of a possible killer, said Christopher Combs, special agent in charge of the bureau’s San Antonio division according to the New York Times. “We don’t know who is behind these attacks. We don’t know whether they will continue,” said Mr. Combs in an interview with the New York Times.

The specialty agents from the FBI and ATF were trying to understand whoever was behind the elusive bombings. The ATF and FBI agents were trying to find out why serial bomber were using this level of violence targeting the city of Austin according to the New York Times.

The police, FBI and the ATF have been alerted to hundreds of packages deemed suspicious, as Austin residents have phoned and emailed family and friends to verify the origin of packages before opening them according to the New York Times.

Perpetrator on the loose, what authorities are looking for to crack the latest bombing attack

Since the bombings began three weeks ago, authorities have been warning people to pay extra attention to suspicious-looking packages like delivered boxes or backpacks. Authorities have cautioned residents of Austin to not touch any suspicious packages that look dangerous. Brian Manley, Austin Police Chief said the tripwire device design required an extreme higher level of skill to create and serve as a “significant change” in an interview with the Associated Press.

According to the Associated Press, while the authorities said the earlier bombings appeared targeted, the latest attack appeared to have hurt anyone who happened to walk by.

In an interview with the Associated Press, Christopher Combs, FBI agent in charge of the bureau’s San Antonio division, “the plan went up a little bit --- well, it went up a lot yesterday with the tripwire,” he said. Fred Milanowski, agent in charge of the Houston division of Alcohol, Tobacco and Firearms, said in an interview with the Associated Press, the latest makeshift device was tied to a metal yard sign near the head of a hiking trail. “It was a thin piece of wire, the wire was a type of fishing line, “he said. “The wire tied to the sign would have been very difficult for someone to see.”

Milanowski said the FBI, ATF and Austin authorities have checked hundreds of leads since the bombings began three weeks ago.

The authorities have had “persons of interest” in the cases, however the people they had so far didn’t led to much according to the Associated Press. The Austin police have asked anyone with surveillance cameras at their homes to come forward with the footage on the chance it captured the suspicious serial bomber or vehicles according to the Associated Press.