Grenoble, France ? French anti-terrorism judges ordered the arrest Tuesday of eight suspects in a deadly Tunisia synagogue bombing that authorities have linked to the al-Qaida terrorist network. Among those detained were the parents and brother of the suspected bomber.

Nineteen people, including 14 German tourists, were killed when a truck laden with gas tanks exploded outside the Ghriba synagogue on the Tunisian island of Djerba.

French Interior Minister Nicolas Sarkozy said in a statement that documents seized during the arrests Tuesday near the southern city of Lyon appeared to be directly related to the April 11 explosion.

French authorities believe the driver of the truck was a Tunisian identified as Nizar Naouar. He is believed to have carried out the attack with an unidentified accomplice who also lived in the North African country.

Naouar is thought to have died in the explosion, but officials have not said what happened to his alleged accomplice.

Among those detained Tuesday were Naouar’s parents and his brother, Walid Naouar, 22, according to Lyon prosecutor Christian Hassensrat said.

Three other people close to the family were also detained.

France’s leading anti-terrorism judges, Jean-Louis Bruguiere and Jean-Francois Ricard, ordered the arrests as part of an ongoing investigation into the attack, the Interior Ministry said.

The suspects were taken into custody in Lyon for questioning by agents from France’s counterintelligence service. Under France’s tough new anti-terrorism law, authorities can hold the suspects up to four days without charging them.

The Ghriba synagogue in Djerba, Tunisia, the oldest synagogue in Africa, is shown April 12, the day after a gas truck explosion killed 19 people. French police announced Tuesday that eight suspects were arrested near Lyon, France, in connection with the attack.

Police in Lyon said it was too soon to determine whether the family played any role in the attack but their arrests had been planned for some time because of their “peripheral interest” to the case.

At the time of the attack, members of the Naouar family said they were shocked at their relative’s alleged connection to the explosion.

“We have nothing to hide, we’re just looking for the truth,” Walid Naouar told The Associated Press in a telephone interview a week after the attack.

Walid was later detained by French border police at the Lyon airport for lacking proper French papers. He was threatened with expulsion to Tunisia, but the process was halted because of a technicality.

The Ghriba synagogue is believed to be the site of Africa’s oldest synagogue believed to have been built about 2,500 years ago.

According to tradition, the first Jews came to Djerba in biblical times, bringing a stone from the ancient temple of Jerusalem that was destroyed by the Babylonians in 586 B.C. The stone is kept in a grotto at Djerba’s synagogue.

Djerba is one of the country’s most popular beach resorts as well as the symbolic hub of the Muslim North African nation’s approximately 2,000-strong Jewish community.

At the time of the April blast, the synagogue was full of tourists.