Updated

Although federal prosecutors laid out their case on the first day of the trial of a former Iowa letter carrier accused of sending letters and dud pipe bombs to investment advisers, the defendant refused to offer a rebuttal.

Assistant U.S. Attorney Patrick Pope contended in a Chicago courtroom Tuesday that John Tomkins methodically gathered information about those he threatened, and shared it to demonstrate he could find and kill them anytime.

Tomkins, 47, is representing himself, and the judge told the jury the defendant will give an opening argument when prosecutors finish presenting their evidence. Instead, Tomkins sat impassively, jotting down notes as Pope laid out how he allegedly ratcheted up the threats with information he'd collected — including a photograph he's accused of taking after driving from his Dubuque, Iowa, home to the suburban Chicago house of a secretary for one of the advisers.

"'Do you know who lives there?'" Pope said Tomkins wrote in a letter that included the photograph. "'I do.'"

Prosecutors allege Tomkins sent letters from 2005 until 2007 that threatened to kill those who received them, their families and neighbors unless they took action to raise the stock prices of 3COM Corp. and Navarre Corp., in which Tomkins had invested. They allege he mailed the pipe bombs from a suburban Chicago post office in 2007.

Tomkins, who Pope said identified himself in some of the letters as "The Bishop," allegedly taunted the people who received them.

"'Bang, you're dead,'" Pope quoted from one of the letters that accompanied a pipe bomb. "'The only reason you're alive is that I did not attach one wire.'"

Prosecutors said the pipe bombs were real and would have detonated had all the wires been attached. Pope said the letters included a threat that the advisers better drive up the stock prices by a deadline he gave them or he would send more bombs, making sure to "connect all the wires," before ending with the words "Tick, tock" or "Time's up."

Tomkins is charged with mailing threatening communications, illegal possession of a destructive device and using a destructive device in connection with a crime of violence.

Pope acknowledged Tomkins left no fingerprints on any of the letters or bombs. At least one letter said the sender had been careful not to leave a fingerprint or any DNA that could link him his plot.

But searches of Tomkins' home, his computer and two storage lockers revealed drafts of threatening letters, and bomb-making materials that matched those used in two pipe bombs, Pope said. He also said investigators found financial records showing Tomkins had purchased stock in the two companies he wanted his victims to also invest in so that the stock price would rise. And, he told jurors, investigators found evidence of the photograph of the suburban Chicago house on Tomkins' computer.

"He tried to delete it but he couldn't," Pope told jurors.

Tomkins has been in custody since his arrest in 2007 on his way to Dubuque. The trial is expected to last about two weeks.