Jordanian authorities have launched an investigation into four politicians who have been accused of expressing sympathy for Abu Mus'ab al-Zarqawi.
Hundreds of Jordanians protested against the politicians
The four members of the Islamic Action Front visited his family to offer condolences after he was killed in an American air strike in Iraq last week.
A spokesman said complaints had been received from the families of people killed in bombings in Amman last year.
The attacks had been carried out by Zarqawi's group, Al-Qaeda in Iraq.
Government spokesman Nasser Jawdeh said the investigation would determine whether the men had instigated sectarianism and incited conflict.
The four were detained on Sunday.
Hundreds of pro-government supporters staged a protest against the politicians on Monday and called for the dissolution of parliament.
The triple attacks on western targets in the Jordanian capital killed 60 people.