A Texas family is on lockdown in the wake of the Austin bombings.
Mike and Stacy Murphy and their children are among Austin residents ordered to stay in their homes as authorities make sure there are no more tripwire bombs in their neighborhood.
"It’s scary," Stacy Murphy told Inside Edition. “Thinking about something like this happening in your backyard or next door is really an unpleasant thought.”
"We heard this big boom and that was obviously concerning and once we heard that was an explosion, it was pretty distrustful for the kids," he added. '
The police response in the area was massive.
"We heard sirens just coming and coming," Stacy said. "There were a lot of tears and a lot of ‘this might happen to us and how do we be safe?'"
Sunday's bombing triggered a police curfew in the affluent Austin neighborhood called Travis Country, where some homes sell for $700,000 or more.
The latest explosion was caused by a tripwire, which poses new fears for law enforcement.
"With this tripwire, this changes things," Christopher Combs, special agent in charge of the FBI’s San Antonio office said Monday during a press conference. “It’s more sophisticated. It’s not targeted to individuals. We’re very concerned that with tripwires, a child could be walking down the sidewalk and hit something."
Authorities also issued a plea for the person responsible, a "serial bomber," to come forward.
“I will reach out to the suspect or suspects and ask that you contact us, ask that you reach out to us," Austin Police Chief Brian Manley said Monday. "Communicate with us so that we can put this to an end. There are innocent people getting hurt in this community and it needs to come to a stop."
Former Navy SEAL Jonathan Gilliam demonstrated the construction of a tripwire by rigging one on a light switch in the Inside Edition office. He placed a wire on the bottom of a door frame, which would activate the light switch as soon as someone walked into it.
Gilliam also gave his take on the Austin bomber, saying, "Obviously this person has done their homework."
He added: "You are seeing someone who has had training because that is not a one-off and it is probably going to work," he said. "This is somebody who has probably done this over and over to the point that they have gotten pretty good at it."
The new blast came just hours after police upped the reward in the hunt for the suspect to $115,000.
Like the rest of the country, residents were watching the NCAA tournament when the blast rocked the neighborhood. Two people were injured.
Sunday's explosion was the fourth package attack in Austin this month. Two men have been killed and others injured in three bombings, one on March 2 and two on March 12.
Just the day before the latest blast, an Austin concert by The Roots during the SXSW festival was canceled due to a bomb threat.