TEXAN TERROR

THE hunt for the serial bomber who has been leaving deadly explosives in packages on doorsteps in Austin, Texas, took a sinister turn when investigators said the fourth and latest blast was triggered along a street by a nearly invisible tripwire.

“The game went up a little bit — well, it went up a lot yesterday with the tripwire,” Christopher Combs, FBI agent in charge of the bureau’s San Antonio division, said yesterday.

Two people have now been killed and four wounded in bombings over a span of less than three weeks.

The latest happened Monday in southwest Austin’s quiet Travis Country neighborhood, wounding two men in their 20s who were walking in the dark.

They suffered what police said were significant injuries and remained hospitalised in stable condition.

Police haven’t identified the victims, but William Grote said his grandson was one of them.

Mr Grote said one of them was riding a bike in the street and the other was on a sidewalk when they crossed a tripwire.

“It was so dark they couldn’t tell and they tripped,” Mr Grote said. “They didn’t see it. It was a wire. And it blew up.

“Both of them were bleeding profusely.”

That was a departure from the three earlier bombings, which involved parcels left on doorsteps that detonated when moved or opened.

Investigators are looking at a variety of motives, including domestic terrorism or a hate crime. Police and hundreds of federal agents are investigating, and the reward for information leading to an arrest has climbed to $115,000.

“We are clearly dealing with what we believe to be a serial bomber at this point,” Austin police Chief Brian Manley said, citing similarities among the four bombs. He would not elaborate, though, saying he didn’t want to undermine the investigation.

While the first three bombings all occurred east of Interstate 35, a section of town that tends to be more heavily minority and less affluent, Monday’s was west of the highway. Also, both victims this time are white, while those killed or wounded in the earlier attacks were black or Hispanic.

Those differences made it harder to draw conclusions about a possible pattern, further unnerving a city on edge.