Federal Affidavit Links Nichols to Bomb-Making Plot : Probe: Document unveiled in court says components for explosive were found in suspect’s home. It portrays him as expert who assembled the deadly mixture.

Government prosecutors unveiled an affidavit Thursday that links Terry L. Nichols to the making of a bomb used to shatter the federal office building in Oklahoma City and portrays him as a key conspirator with accused bomber Timothy J. McVeigh in the blast.

The 10-page document was released during a short court appearance for Nichols, 40, at a federal prison here. In it, federal authorities contend that in the four days leading up to the April 19 bombing, Nichols purchased large amounts of diesel fuel and his neighbors reported seeing a large Ryder rental truck at his house and at a storage bin he kept near his home in Herington, Kan.

The affidavit also asserts that the Ryder truck and a pickup truck matching one owned by Nichols were spotted on the morning before the bombing at a fishing lake not far from Herington. Officials said they believe that the fuel oil and large amounts of ammonium nitrate fertilizer were mixed together at the lake, then transported in the Ryder truck to Oklahoma City.

To bolster their claim that Nichols is a bomb expert and the brains behind assembling the deadly mixture, the affidavit said federal agents recovered blasting caps, bomb cords, a fuel meter and “several containers of ground ammonium nitrate” in a search of his home after he voluntarily surrendered in the case three weeks ago.

At his arrest April 21, Nichols told investigators that he and McVeigh, 27, visited downtown Oklahoma City three days before the bombing. He acknowledged that he knows “how to make a bomb by blending ammonium nitrate with diesel fuel, which could be detonated by blasting caps,” the affidavit said.

And Nichols told the FBI that two days after the bombing, he sprayed some of the ammonium nitrate on his lawn after reading in newspapers that the fertilizer was used in the Oklahoma City blast--an explanation that federal sources said they regard as an attempt to hide his role.

During his court appearance, Nichols was chained at the wrists and around the waist and wore a rumpled white T-shirt, khaki slacks and blue loafers. He appeared pale and somewhat confused during the hearing, which lasted less than 30 minutes and took place in the visitors room at the Federal Correctional Institution here. He spoke only when addressed by U.S. Magistrate Ronald L. Howland.

Asked if he understood the felony charges filed against him, Nichols said simply: “Yes, your honor.”

Nichols has denied any involvement in the bombing. The federal complaint against him charges that he “did maliciously damage and destroy by means of fire and an explosive” the Alfred P. Murrah Federal Building in nearby Oklahoma City. U.S. Atty. Patrick Ryan of Oklahoma City reminded Howland that the maximum punishment in the case is death.

The blast killed 167 people and injured 400. Nichols now awaits a preliminary hearing scheduled for next Thursday, when prosecutors must divulge enough evidence to keep him in custody and move forward to trial.

Also under way is a federal grand jury investigation in Oklahoma City that the government hopes will produce a broad conspiracy indictment against Nichols, McVeigh and others.

Nichols’ ex-wife, Lana Padilla, has been called to testify before the grand jury.

The affidavit says Nichols has said he met McVeigh during Army basic training in 1988 in Georgia. They later served together at Ft. Riley, Kan., not far from Herington. “Over the years they have occasionally lived together, operated a business together involving the sale of Army surplus items and firearms at gun shows throughout the United States,” the affidavit says.

Nichols told investigators that he “was with McVeigh in downtown Oklahoma City” on April 16. He said McVeigh told him on April 18 that he had items in a Herington storage shed, the affidavit said. McVeigh said that if he did not pick them up himself, “Nichols should do it for him.” Nichols said he picked up a rifle and other items the day after the blast.

Nichols also told the FBI several times that he hoped agents “would not mistake household items” for bomb-producing materials found in his house. “In particular,” the affidavit said, “Nichols told agents that he had several containers of ground ammonium nitrate which he said he sells as plant food fertilizer at gun shows.”

At his home, agents seized guns, four white barrels with blue lids made from material resembling blue plastic fragments found at the bomb scene and a receipt for 40 50-pound bags of ammonium nitrate purchased in September from the Mid-Kansas Co-op in McPherson, Kan. The FBI said it found a fingerprint on the receipt that matched McVeigh’s.

The affidavit said Nichols, often using false names, had rented three storage bins in Herington and nearby Council Grove, Kan.

The FBI said it also found a November letter from Nichols to McVeigh. In the letter, Nichols reportedly said that in the event of his death, McVeigh should “clear everything out of” one storage bin and “also liquidate” another storage unit. The letter allegedly ended with Nichols telling McVeigh he would be on his own and to “Go for it!!”

According to the affidavit, Nichols purchased an unspecified amount of diesel fuel from a Conoco service station in Manhattan, Kan., on April 15. He purchased another 21.59 gallons of diesel fuel from a Conoco station in Junction City, Kan., on April 16.

On April 17, he placed a phone call from his home to McVeigh at his room in the Dreamland Motel in Junction City. That night, a Ryder truck was seen parked behind Nichols’ home in Herington, the affidavit said.

During that same week, witnesses told the FBI, they saw both the yellow Ryder truck and Nichols’ blue pickup at the storage shed in Herington. And at the Geary State Fishing Lake near Junction City, where witnesses spotted both the Ryder truck and Nichols’ pickup, an FBI agent noticed an unusual spot on the ground that indicated that diesel fuel and fertilizer had been blended there.

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In a related development Thursday, a federal grand jury in Detroit indicted Nichols’ brother, James D. Nichols, 41, on charges of entering into a conspiracy to possess destructive devices with his brother, McVeigh and “other persons” from 1988 to April 21, when both of the Nichols brothers were taken into custody. Those charges, however, are not directly related to the Oklahoma City blast.

The indictment followed a federal arrest complaint against the Nichols on nearly identical charges. The indictment named only James Nichols, however, because Terry Nichols already faces a more serious charge--the Oklahoma City bombing--a Justice Department spokesman said.

James Nichols, whom federal investigators are hoping to link directly to the bombing, also was charged with possessing on April 21 unregistered parts to be converted into a destructive device.

Meanwhile, it was learned that the FBI is searching for a federal fugitive that McVeigh is believed to have attempted to contact last fall in Kingman, Ariz. The fugitive, Stephen Garett Colburn, is reportedly being sought by authorities in the Los Angeles area on charges of illegal possession of firearms.

The FBI has been searching for Colburn, who also is being sought by U.S. marshals, for at least a week, a source close to the investigation said Thursday night. Colburn was described as an extreme right-wing radical and firearms enthusiast who has made statements indicating he has the “mind-set” for violent acts against the government, the source said.

Serrano reported from El Reno and Ostrow from Washington. Times staff writer Michael Ross in Washington contributed to this story.