Indonesia police said Tuesday they had made their first arrest in the Bali (search) bombings — a 45-year-old construction worker who shared a rented house on the island with the three homicide bombers before the Oct. 1 attacks.

The arrest of the man, identified only as Hasan, could be the first major break in the case since three homicide bombers blew themselves up in crowded restaurants, killing 20 other people in tourist resorts.

Authorities found the man on Sunday in Jember, a town in neighboring East Java province about 125 miles east of Bali's capital Denpasar. He was sent back to Bali on Monday for questioning, said Capt. Wahyu Wim Hardjanto (search), the chief detective in Jember.

The arrested man shared a house with the three bombers in Denpasar but left the island three days before the attack, said national police spokesman Brig. Gen. Sunarko Ardanto (search).

Under Indonesia's anti-terror law, the father of three can be held for up to seven days before charges are filed, Sunarko said.

Authorities found the severed heads of the three homicide bombers at the sites of the attacks and widely publicized the grisly pictures in hopes of identifying them and anyone who had helped them.

Police received a tip that four men — including the three suicide bombers — had rented a house in a middle class neighborhood on the outskirts of Denpasar.

More than 259 witnesses have been questioned since the attacks on Jimbaran beach tourist resort and the nearby tourist center of Kuta, Sunarko said.

Police detained and questioned several men days after the attack but they were later released on the belief they had no connection to the case.

The Al Qaeda-linked militant group Jemaah Islamiyah, blamed for three other terrorist attacks since 2002 in Indonesia, is believed to be involved in the triple homicide bombings.

Rumors have swirled for days that police were close to arresting the suspected masterminds and Southeast Asia's most-sought fugitives — Malaysians Noordin Mohamed Top and Azahari bin Husin. But so far the two alleged leaders of Jemaah Islamiyah remain on the run.

At least 10 people at Manega Cafe, one of the bombed restaurants, said a suspicious man was seen examining the area on the morning of the explosions, said Col. Bambang Kuncoko, another police spokesman.

"A man wearing a black undershirt and trousers was walking back and forth in front of the cafe and looked very confused," Kuncoko quoted witnesses as saying.

Eleven witnesses at another targeted cafe said they thought one of the alleged bombers once lived in a rented house in Denpasar, he said.