Indonesian authorities named four new suspects today in their investigation of last month's bombing attack in Bali as investigators focused on links to regional terrorism within the Indonesian family of the prime suspect in the blasts, who is now in custody, and three of his brothers, who are at large.

National Police Chief Da'i Bachtiar said today "it is very possible" that an Islamic teacher named Mukhlas, who is an older brother of chief suspect Amrozi, may now be acting as operations chief of the regional militant Islamic network Jemaah Islamiah, and that Mukhlas is a key suspect in the Oct. 12 explosions, which killed almost 200 people, most of them foreign tourists.

Jemaah Islamiah has been headed by Riduan Isamuddin, better known as Hambali. The change in leadership may have taken place because Hambali, the region's most-wanted terror suspect, left for Afghanistan, Bachtiar said. Intelligence officials say Hambali is the main link between Jemaah Islamiah and al Qaeda.

Beginning with last week's arrest of Amrozi, a 40-year-old motorcycle mechanic and the alleged field commander in the Bali operation, police have made steady progress in unraveling the bombing plot and identifying suspects in the worst act of terrorism since Sept. 11, 2001.

Today Bachtiar interrogated Amrozi in a glass-enclosed room, allowing reporters to see, though not hear, their discussion. After the hour-long interrogation, Bachtiar told reporters that Amrozi was in good condition, adding that he was fasting for the Muslim holy month of Ramadan.

Mukhlas and Amrozi have long-standing ties to radical Muslim cleric Abubakar Baasyir, with the older brother graduating in the early 1980s from an Islamic boarding school in central Java founded by Baasyir and becoming an Arabic language teacher there.

When Baasyir fled to Malaysia in 1985 to avoid a crackdown on Islamic militants by then-President Suharto, Mukhlas joined him in exile, according to acquaintances from the school. He lived intermittently with Baasyir in Malaysia over the next 11 years, according to teachers who knew him in central Java. Mukhlas is still in Malaysia, according to another brother, Mohammed H. Khozin, who founded an Islamic boarding school in East Java similar to Baasyir's.

Singaporean authorities say they believe Mukhlas is the regional chief for the Malaysian wing of Jemaah Islamiah, which includes Singapore. Officials there said he was involved in a failed plot to blow up the pipelines that supply Malaysian water to Singapore. He also ran an Islamic school in Johor, in the southern Malaysian peninsula, they said. Mukhlas, they said in September, was wanted by Malaysian authorities and had gone into hiding.

Amrozi spent many years traveling between Malaysia and Indonesia, as well as in other Southeast Asian countries. He first visited Malaysia in 1985, police said, and worked there in construction. In the early 1990s, he studied Islam under his brother and Baasyir in Malaysia, Bachtiar said.

It was then that Amrozi began to believe in the need to defend Islam from kedholiman, an Arabic word meaning threat to Islam, Bachtiar added. Amrozi began to idolize Mukhlas, Baasyir and a third cleric, Jafar Umar Thalib, the leader of an Islamic militia, Laskar Jihad, whom Indonesian police arrested last spring on charges of inciting hatred.

According to Indonesian investigators, both Mukhlas and Amrozi spent time in Afghanistan.

National police spokesman Ahmad Basyir Barmawi told the Associated Press that teams of investigators have been sent to Singapore, the Philippines and Malaysia to search for evidence in the Bali blasts and uncover the terrorists' regional network.

In his interrogation today, Amrozi looked fresh and relaxed, occasionally laughing, as he spoke to Bachtiar.

Amrozi told Bachtiar that a man named Imam Samudra asked him to buy the chemicals to make the powerful bomb that destroyed the Sari Club in Bali's famed Kuta district as well as the Mitsubishi L-300 van used to carry the bomb.

Samudra, also known as Hudama, is one of four new suspects in the Bali attack named by police today. Authorities had already been searching for him because of his alleged involvement in a series of church bombings on Christmas Eve 2000, including one on the island of Batam near Singapore.

Baasyir is under arrest for suspected involvement in the same church blasts.

The three other suspects named today were identified only as Umar, Idris and another Umar, which is in keeping with the Indonesian tradition of using only one name. Complicating this case is the fact that most of the suspects also have aliases.

Amrozi said that he, Samudra, Idris and another man, named Martin, met more than once in Solo, in central Java, to discuss the bomb plan, according to Bachtiar's account. The three others promised to give Amrozi money to buy the materials for making the bomb. Amrozi told police that Idris gave him the equivalent of more than $5,000 in U.S., Singaporean and Malaysian currency.

Amrozi told Bachtiar that his "friends" made the bomb. According to Bachtiar, the men, whom he did not name, met on Oct. 6 in Denpasar, the capital of Bali. On that day, Amrozi visited one of the rooms rented by his friends and saw a Nokia 5110 cell phone with a cable linking it to the bomb, Bachtiar said.

Amrozi, who was raised in a remote farming village, Tenggulun, in East Java, has 12 brothers and sisters. Besides Mukhlas, two other brothers, Ali Imron and Ali Fauzi, are wanted by police in connection with the bombings. They are both teachers at Al Islam, the Islamic school in Tenggulun founded by their brother Khozin.

Bachtiar also played a tape of apology by Amrozi. "I apologize to my parents, brothers and sisters and other relatives over the incident that has caused so much trouble," he said. "Those involved were me and my younger brother Ali Imron."

According to Bachtiar, Amrozi heard about the bombings in Bali on the radio at 7 a.m. on Oct. 13. He was "very excited" to hear that "his bomb [attack] worked," Bachtiar said. Then Amrozi laughed. When his wife asked him why he was laughing, Bachtiar said, he could not explain why.

Sipress reported from Kuala Lumpur, Malaysia.

Amrozi, the main suspect in the Bali attack, told police he was given money to buy bomb materials.