After a five-day reign of terror that had rural Americans nervously eyeing their mailboxes, a cell phone signal and an alert motorist led to the arrest of a 21-year-old college student accused of planting pipe bombs in several states.

Luke J. Helder, of Pine Island, Minn., was charged Tuesday after a high-speed chase along a desert highway followed by a phone conversation with an FBI negotiator and his parents.

After Helder surrendered, bomb squads called to the scene along Interstate 80 some 50 miles east of Reno dismantled five pipe bombs found in the car, said Maj. Rick Bradley of the Nevada Highway Patrol.

Early Wednesday, a handcuffed Helder was led into the Washoe County Jail by four federal agents. Wearing a black Kurt Cobain T-shirt and long, baggy tan shorts, his hair mussed, Helder offered no comment.

Helder was enrolled as a junior majoring in art and industrial design at the University of Wisconsin-Stout, located in Menomonie, Wis. Former classmates said Helder loved the grunge band Nirvana and was preoccupied with Cobain, its lead singer, who committed suicide.

The capture came just eight hours after the FBI issued an all-points bulletin for Helder and said it wanted to question him about the 18 pipe bombs found since Friday.

Six people — four letter carriers and two residents — were wounded by bombs left in mailboxes in Illinois and Iowa. Twelve other bombs found in Iowa, Nebraska, Colorado and Texas did not explode. Most of the bombs were accompanied by anti-government propaganda warning that more ``attention getters'' were on the way.

In response, authorities asked residents in several states to leave their roadside mailboxes open to give nervous letter carriers a clear look inside.

After Helder's license plate and car description were broadcast nationwide Tuesday, a motorist on Interstate 80 spotted Helder's vehicle and tipped off authorities. He was pulled over after a 40-mile chase that reached 100 mph.

``The FBI contacted him on his cell phone and started negotiations with him, and asked us to back off,'' said Bradley. ``Then he slowed down.''

FBI agent Terry Hulse said Helder telephoned his parents during the chase and was patched through to an FBI negotiator. He said Helder stayed on the phone with the FBI after pulling over east of Fernley and volunteered to surrender if he was not harmed.

Authorities said Helder dropped a gun out his car window and was taken into custody without incident. At least one other gun was found in the car, authorities said.

Federal prosecutors in Iowa charged Helder with using an explosive to maliciously destroy property affecting interstate commerce and with using a destructive device to commit a crime of violence. The charges carry penalties of up to life in prison and fines of $250,000. In addition, he was booked on a federal firearms charge.

U.S. Attorney Charles W. Larson said Helder was responsible for the injuries suffered Friday by a woman in Tipton, Iowa. Federal charges also were expected to be filed in Illinois, Larson said.

Washoe County Sheriff Dennis Ballam said Helder would go before a federal magistrate on Wednesday in Reno, where he is likely to be held for a few days before being transported to face charges.

FBI agent Jim Bogner in Omaha, where the investigation is centered, refused to say how Helder had become part of the case.

But a college newspaper in Wisconsin said it gave the FBI a seven-page letter Tuesday that it received over the weekend and was signed with Helder's name.

The letter was postmarked in Omaha on Friday — the day the first bombs were found in Iowa and Illinois, and a day before bombs turned up in Nebraska — and its first page is identical to the anti-government notes found with the bombs.

The letter also said, in part: ``I will die/change in the end for this, but that's OK, hahaha paradise awaits!''

The FBI wouldn't comment on the letter sent to The Badger Herald at the University of Wisconsin at Madison.

As the search for Helder intensified, his father at the family's home in Minnesota read a statement urging his son to call.

``I really want you to know that Luke is not a dangerous person,'' Cameron Helder said. ``I think he's just trying to make a statement about the way our government is run. I think Luke wants people to listen to his ideas, and not enough people are hearing him, and he thinks this may help.''

Helder was enrolled at the University of Wisconsin-Stout but had apparently not attended classes since at least April 24, a school official said. He played guitar and sang in a punk rock band called Apathy.

FBI agents searched Helder's apartment in a two-story building near campus. Menomonie police spokesman Brian Swantz said two houses nearby were evacuated because of ``potential danger'' but refused to elaborate.