The FBI issued a nationwide alert yesterday for a 21-year-old college student suspected of planting 18 pipe bombs in a campaign that has terrorised the American Midwest.
Officials said they wanted to talk to Luke Helder, an arts student, who was described as an intelligent young man with strong family ties and a taste for grunge rock.
"We encourage Luke Helder to make contact with us," said FBI agent James Bogner, as he held a small photograph of a neatly dressed young man with close-cropped brown hair. "We do not want to see him harmed or public safety harmed."
The hunt for Mr Helder, a student at the University of Wisconsin-Stout in Menomonie, Wisconsin, was centred in west Texas, where the latest pipe bomb was found on Monday in Amarillo. The FBI's bulletin said he was armed and dangerous but Mr Bogner refused to say if he were carrying a gun or whether the description referred to bomb materials. He said: "We need to talk to Luke Helder and we need to try to resolve this incident."
Six people have been hurt by the bombs, which were placed in mailboxes in Illinois, Iowa and Colorado. The FBI described the planting of the bombs as an act of "domestic terrorism".
Mr Helder's college said he was majoring in the arts with a concentration of his studies in industrial design. He was said to be a fan of the grunge rock band Nirvana and used to play in a rock band called Apathy. Police said he did not have a criminal record .
As with the previous 17 bombs, the one discovered in Texas was accompanied by a letter. Whether it contained the same anti-government rants found with the others was not clear last night. One letter said: "The United States strives to provide freedom for their people. Do we really have personal freedom? I've lived here for many years, and I see much limitation. Do you people enjoy this trend of limitation? If not, change it."Reuse content