The killings of Sajida Mubarak al-Rishawi's three brothers in Iraq's volatile Anbar province is being considered as a possible motivation behind her effort to take part in last week's triple bombings, which killed 57 people.
Friends of al-Rishawi, who come from Anbar's provincial capital of Ramadi, said three of her brothers were killed by US forces.
Thamir al-Rishawi, regarded as a known member of an al-Qaida in Iraq terror cell operating in Anbar, was killed during the April 2004 US operations in Falluja when an air-to-ground missile hit his pickup.
Two other brothers, Ammar and Yassir, were killed in two attacks against US troops in Ramadi, said the two friends, who declined to be identified further because they feared retribution.
Police arrested the would-be bomber on Sunday in a safe house in western Amman after the al-Qaida in Iraq terror group issued an internet statement saying a woman was among the four Iraqi attackers.
Al-Rishawi revealed no motive for trying to bomb the Radisson SAS hotel in a televised confession on Sunday, saying only that she was brought to Jordan from Iraq by her husband, who fitted her with an explosives belt and told her it would be used in a bombing attack.
Jordanian intelligence officials say their interrogation of al-Rishawi, which could last for about a month before she is charged, has been going slowly, with few details emerging of her motivation behind taking part in the plot.
Jordan unveiled tough anti-terror
measures after the hotel blasts
She could face the death penalty if convicted of conspiring to carry out a terrorist attack that killed people and possessing explosives with the aim of using them illegally, according to a senior security official close to the interrogation.
Al-Rishawi said in her confession that she wanted to join her husband in attacking the Radisson, but her bomb, packed with 10kg of RDX explosives and ball-bearings, malfunctioned.
Also on Tuesday, Jordanian officials announced tough anti-terror measures in an effort to stop further foreign activists operating covertly in Jordan.
Interior Minister Awni Yirfas announced new regulations demanding that all Jordanians should notify authorities within 48 hours of any non-Jordanian renting an apartment or house.
"Violators of this regulation will face legal ramifications," Yirfas said without elaborating.
Authorities will demand that Jordanians provide the names, nationalities and passport details of any foreigner renting a property in the kingdom.
In a further response to the hotel bombings, Jordan has begun drafting tough anti-terrorism laws, the country's first that target terror crimes, a top Interior Ministry official said.
The blasts in three Amman hotels
killed 57 people
The draft law, which will likely be ready for parliament debate early next year, will let authorities hold any suspect for questioning indefinitely, the official said on condition of anonymity because he was unauthorised to speak to the media.
The anti-terror law will propose issuing penalties on "those who would expose the lives and properties of citizens to danger inside and outside the country".
Anyone condoning or justifying terrorist actions or supporting them financially will face penalties under the proposed law, the official added.
The two other targeted hotels, the Grand Hyatt and Days Inn, were bombed by Iraqi men Safaa Mohammed Ali and Rawad Jassem Mohammed, both 23, Jordanian officials said.
The US military command in Iraq said American troops had detained an Iraqi of the same name as one of the bombers, Safaa Mohammed Ali, during operations in Falluja in November 2004 but released him after two weeks because there was no "compelling evidence" that he posed a security threat.
The military could not confirm whether the man was among the three Amman hotel bombers.
Police believe al-Rishawi may provide vital clues to al-Qaida in Iraq and possibly al-Zarqawi's whereabouts.