HELENA, Mont. - As federal agents searched for proof that Theodore Kaczynski left his Montana cabin to mail bombs, two people said yesterday they had seen the hermit in Sacramento, Calif., in the area where the Unabomber mailed his last four bombs.

Frank Hensley, a desk clerk at the Royal Hotel, next door to the bus depot in downtown Sacramento, told The Associated Press he saw Kaczynski in the neighborhood or staying at the hotel almost annually during the last five years. He stayed at the hotel two or three times, usually in the late spring or summer, Hensley said.

''If it wasn't for all this, I'd be expecting to see him about now,'' Hensley said, referring to Kaczynski's recent arrest.

At a Burger King restaurant next to the Sacramento bus depot, manager Mike Singh said he saw Kaczynski a few times in recent years. On one occasion, Kaczynski was carrying an armload of books, Singh said.

''He said he was doing research and he had a breakfast sandwich,'' he said. ''He looked like one of those bums who come in in the morning and have a sandwich and cup of coffee and walk out.''

FBI spokesman George Grotz confirmed that agents were investigating whether Kaczynski had traveled to the Sacramento area.

Federal investigators tracking Kaczynski's movements are trying to learn how the former math professor, who had no visible means of support, could get to other states where the Unabomber's bombs were mailed or left.

They reportedly are checking whether he rode buses to those states; two bus line employees in Montana told the AP that Kaczynski was a passenger numerous times.

Kaczynski, 53, was taken into custody at his cabin near Lincoln, Mont., on Wednesday and is being held without bail in a Helena jail. He has been charged in federal court with possession of bomb-making materials.

The charge is intended to keep Kaczynski in custody while investigators build a case against him for the Unabom attacks that killed three people and injured 23 in nine states over the past 18 years.

Meanwhile, the painstaking search of Kaczynski's 10-foot-by-12-foot cabin continued yesterday. Grotz said investigators were combing the cabin and the surrounding forest.

The cabin search already has turned up a partially completed pipe bomb, bomb-making chemicals and components, and notes on making bombs.

One law enforcement official said a typewriter found in the cabin appears to be the one the Unabomber used to type his 35,000-word manifesto and letters. Another said investigators defused a live bomb in the cabin on Friday that they believe was intended for someone in particular.

Hensley said FBI agents approached him in March, showing him Kaczynski's photo.

''I recognized him right away,'' he said. ''I remembered his face.''

Hensley said Kaczynski stayed at the hotel two or three times in the late spring or early summer, and his stays lasted no longer than a week. He said he didn't recall the years he stayed in the hotel.

Hensley said FBI agents collected registration cards from the Royal and three other hotels in the neighborhood under the same ownership.

The agents were searching the Royal records for a guest registered by the last name of Konrad, Hensley said. He said they did not explain why.

The last four bombs from the Unabomber were mailed from Northern California: Two bombs postmarked in Sacramento exploded in June 1993, wounding one person in San Francisco and another at Yale University in New Haven, Conn

Another bomb mailed from San Francisco in 1994 killed a New Jersey advertising executive. And a fourth bomb postmarked in Oakland, Calif., exploded April 24, 1995, killing a timber industry lobbyist in Sacramento.

Years earlier, on Dec. 11, 1985, a man was killed by a bomb he found near his computer rental store in Sacramento.

U.S. attorneys from California, New Jersey, Montana and Utah were scheduled to meet Monday in Washington, D.C., to discuss where to hold the Unabomber trial.