Polish Police Launch Manhunt for Bomber : Crime: Suspect allegedly planted device near Krakow’s Old Town last week. Now residents fear threat of explosions at 10 sites in city.

Police set up roadblocks around the medieval city of Krakow and launched a nationwide manhunt Wednesday for a miner-turned-terrorist who has threatened to blow up the city in southern Poland.

About 1,000 Krakow police officers, more than a quarter of the police force, joined the search for Sylwester Augustynek, a 50-year-old burglar and thief who police say developed a knack for sophisticated explosives while working in the nearby Silesian mining region.

Augustynek, who has used the moniker “Gummi Bear” in telephone calls and letters, allegedly planted a bomb last Thursday at the bus terminal near the city’s 13th-Century Old Town, one of the most popular tourist destinations in Poland. Although the bomb did not explode, anti-terrorist squads later detonated it, hollowing a crater the size of an automobile.

“This is a very serious threat,” said Krakow police spokesman Cezary Butny. “This is the first time we have ever had to deal with a situation where someone is terrorizing the entire city.”

Police have received 28 bomb threats since the bus station bomb last week, leading to evacuations of the courthouse, train station and a university building, but they have found no more explosives. Although hotels and restaurants reported Wednesday that foreign tourists continue to arrive in droves, residents of Poland’s royal capital are living in fear.

“There is general panic,” said Bozena Dzialowska, assistant manager of Wierzynek restaurant in Old Town. “Everyone feels it. I am afraid because I take the bus home and my stop is close to the bus station.”

Officials at the Interior Ministry in Warsaw responded Wednesday by offering a $5,000 reward for information leading to the capture of Augustynek, whom police described as armed and dangerous. Police said he served several years in prison in the 1980s for theft and burglary and has been wanted since last year on charges of auto theft and forgery.

Residents of Trzebinia, a small town near Krakow where authorities said Augustynek was last known to live, told reporters that he often visited but had not lived there for years. Trzebinia police said Augustynek was a member of a local car-smuggling ring, and a woman identified as his girlfriend was quoted in one newspaper as saying: “I know this man. Nothing would surprise me.”

In a rambling letter published Wednesday in the Krakow newspaper Gazeta Krakowska, a man identified as “Gummi Bear” claimed to have hidden 10 bombs across the city and repeated an earlier demand for more than $300,000 in ransom. If authorities did not pay the money, he wrote, he would transform Krakow into a “carnival” by setting off the explosives.

“Long live the carnival in Krakow!” said the letter, which was reprinted in full on the newspaper’s front page. In a perplexing contradiction, it went on to say: “I never, never attack people. . . . My explosives are not armed.”

Authorities tried twice over the weekend to snare the bomber but failed on both occasions. In one phone call to the Krakow newspaper, “Gummi Bear” instructed police to leave the ransom in a bag in a police car in the mountain resort of Zakopane. Police followed the instructions--although they apparently stuffed the bag with a tracking device, not cash--but no one came to claim the cache.

In another phone call to the newspaper, “Gummi Bear” ordered police to drop the money in small bags from a train between Zakopane and Krakow, but the instructions came so late that the train had left before police could make the arrangements.

Although there were doubts raised about the authenticity of the letter published Wednesday, the author offered the first insights into “Gummi Bear’s” motives. The letter was critical of local politicians with ties to the Solidarity movement and of the influence of the Roman Catholic Church, saying less money should be spent on restoring old cathedrals and more on helping local residents.

As a further indication of his political leanings, “Gummi Bear” sent a copy of the letter to Jerzy Urban, the former Communist-era press spokesman who publishes a weekly newspaper critical of the democratic changes in Poland.

“Please do not condemn me,” he wrote to Urban, “not knowing the motives which have driven me to such drastic measures.”