THE LATEST: Trip wire likely used in Sunday explosion, Austin police chief says

AUSTIN – Austin Police Chief Brian Manley said it's likely a trip wire was used in an explosion that sent two people to the hospital with serious injuries Sunday night.

Authorities have been at a home in the 4800 block of Dawn Song Drive since 8:30 p.m. after receiving a report of an explosion. 

Two men in their 20s were taken to St. David's South Austin Medical Center with serious, but non-life threatening injuries. The Austin American-Statesman reported late Sunday night the two men were in "good" condition.

Manley said early Monday morning that the explosion occurred on the side of a neighborhood road and not on a doorstep and that a trip wire was likely used in the explosion. The two men were either riding bikes or pushing their bikes down the road when the bomb exploded, Manley said.

Manley held two media briefings following the explosion. In the first briefing, he reiterated Austin residents should have increased awareness and take extra precaution when dealing with packages. In the second briefing in which he addressed reports of a trip wire, he asked that residents be aware of any suspicious contraptions or devices.

Those living within a half-mile radius of the blast site were asked to remain in their homes until authorities determine it is safe. Early Monday morning, Manley again asked residents to remain in their homes until authorities have had a chance to process the scene.

Manley said they have not yet had the opportunity to thoroughly inspect the blast site and are waiting until daylight to officially confirm a trip wire was used in the Sunday night explosion.

In the first briefing, Manley said authorities were inspecting a backpack at a second site. Authorities have not given an update in that investigation.

The explosion affected the Austin Independent School District's transportation schedule. Austin ISD busses will not be able to travel to the neighborhoods affected. As a result, late arrivals and absences will be excused on Monday.

A man who lives in the area and heard the explosion told KXAN-TV it sounded like thunder. He said the neighborhood is typically quiet and it is relatively secluded.

Manley said early Monday morning that authorities are operating under the assumption the incident is linked to the three package bomb explosions that killed two people and injured two others this month. Authorities will not be able to confirm whether they are linked until they process the scene.

The explosion comes after Manley gave an update on the investigation into the package bombs Sunday afternoon.

According to Manley, more than 500 law enforcement personnel are assisting in the case. Authorities urge anyone who might have information about the bombings to call authorities.

Manley explained that every tip received is logged, assigned and investigated. So far, authorities have addressed more than 400 leads in the bombings and have responded to 735 calls for suspicious packages.

A reward for information leading to an arrest and conviction in the bombings was increased to $100,000. The reward is separate from a $15,000 reward issued by Gov. Greg Abbott. Manley said the reward money is coming from federal partners.

MEDIA BRIEFING 1 - Sunday 11 p.m.:

MEDIA BRIEFING 2 - Monday 1 a.m.: