Four explosions this month in Austin, TX, have the city on edge. The latest occurred on Sunday night and injured two people on bicycles.

Authorities believe this last one was triggered by a trip wire.

The first three incidents happened when packages left on porches exploded. Sunday’s explosion now “changes things” when it comes to safety measures. From KXAN:

Chief Manley said in a follow-up press conference at 1:45 a.m. Monday that the possibility the bomb was triggered by a trip wire and the fact that the explosive device was left next to the road instead of on a front porch like the previous three cases necessitated a new warning to the public:

“We now need the community to have an extra level of vigilance and pay attention to any suspicious device, whether it be a package, a bag, a backpack, anything that looks out of place. And do not approach it. Again do not approach items like that, but instead call 911 to report it so we can go out and make sure it’s safe.”

Initial reports indicate some key differences between the latest bombing and the other three, including that it happened at night, did not occur in east Austin, did not appear to be on someone’s front porch, may have been set off by a trip wire and may not be a package. Police are asking anyone who sees anything suspicious — not just a package — to call 911.

Manley said that they do not have confirmation this explosion is related to the first three, but that they are “working under the belief” that it is.

http://www.foxnews.com/us/2018/03/19/austin-on-edge-after-explosion-leaves-2-injured-cause-blast-unclear.html

Via Fox News

The first explosion killed Anthony Stephan House, 39, on March 2. Two explosions in a matter of hours happened on March 12 that killed one person and injured two more.

Manly said the authorities “have still not ruled out” race being a factor in the bombings. That was the first assumption with the three previous bombings since the victims were black or Hispanic. The victims on Sunday were white.