Police also investigated the theory that two bombs - one attached to an attacker and another ball-bearing-packed package - exploded during the wedding attended by almost 300 Jordanians and Palestinians at one of the hotels hit on Wednesday.
Al-Qaida in Iraq, the group headed by Jordanian-born Abu Musab al-Zarqawi, claimed four Iraqis - including a husband and wife - carried out the near simultaneous bombings on the Grand Hyatt, Radisson SAS and Days Inn hotels.
The attacks killed at least 57 people, including three Americans.
The Jordanian authorities have recovered the remains of only three men believed to have detonated explosives worn underneath their clothing. No female has so far been identified.
Security forces have rounded up scores of people, mainly Iraqis and Jordanians, in the hunt for accomplices in the three coordinated bombings. At least 12 people are being interrogated as suspects linked to the attacks.
The Days Inn bomber argued with hotel staff shortly before detonating a belt packed with up to 22lb of explosives, likely TNT, at the building's entrance, a senior police official said on Saturday on condition of anonymity because he was unauthorised to speak to the media.
The bomber ordered an orange juice and spoke in an Iraqi accent to staff, who asked him to move from an area where he was sitting because it was designated as a "place for families" and not single men, the official said.
"The man became angry and started mumbling words in an Iraqi accent that the waiter believed were insults before leaving the hotel"
Senior police official
"The man became angry and started mumbling words in an Iraqi accent that the waiter believed were insults before leaving the hotel," the official said.
Hotel staff saw the man then kneel to the ground and start tugging at something from under his jacket, apparently fighting with a faulty primer cord for his explosives, which finally detonated, blowing his body apart and killing three members of a Chinese military delegation, the official said.
Waiters also told police that the morning before the attack, two men entered the hotel and appeared to be staking out the premises before leaving shortly after, the official added.
Suspicion on Iraqis
Police had already revealed that the Hyatt bomber also spoke with people in the hotel's lobby in an Iraqi accent before detonating his explosives.
Suspicion about the bombers has increasingly fallen on fighters battling US and Iraqi forces across Jordan's eastern border with Iraq.
Al-Zarqawi, who has been sentenced to death in absentia in Jordan on terrorism charges, is believed to have trained more than 100 Iraqi fighters to carry out bombings in Iraq and possibly elsewhere in the Middle East.
The attacks bore all the hallmarks of al-Zarqawi's group, one of Jordan's top policemen said, adding those hotels and other "unsuspecting places" could be hit again.
Al-Zarqawi has been sentenced
to death in absentia in Jordan
"The threat still exists against those places and others and we are meeting non-stop to determine potential targets and implement required protection," Major-General Mohammad al-Eitan, general director of public security, told a state-run Jordan TV station.
Police are investigating the theory that two bombs - a TNT-laden explosives belt worn by the bomber and a parcel bomb packed with ball bearings - exploded in a ballroom during a wedding at the third hotel, the Radisson, the official said.
Many of those killed and maimed in the Radisson attack suffered wounds caused by ball-bearings, indicating that the TNT-packed belt worn by the bomber was not the only explosive device used, he said.
If TNT was used, it would have had to have been smuggled into Jordan, because that type of explosive is not available in the country, the official added.
Meanwhile, police released details of eight vehicles spotted by witnesses at the hotels at the time of the attacks. It was unclear what role, if any, the vehicles had in the blasts.
Two of the vehicles, a GMC Suburban four-wheel drive and a Mercedes Benz sedan, had Iraqi licence plates, while the six others had Jordanian plates and included several rented cars and a van.
Jordanians across the country are seething over the attacks and thousands have turned out for two days of protests to condemn al-Qaida in Iraq.
While not unaccustomed to terrorist violence and plots, Wednesday's attacks were this kingdom's deadliest ever.
With the bulk of the victims being Arabs and Muslims, Jordanians and many of the kingdom's 400,000 Iraqi expatriates have condemned al-Qaida for turning their sights from US-led occupation forces in Iraq on to fellow Muslims.
Jordanians held a second day of
protests over the hotel bombings
Al-Qaida in Iraq, which has released three statements since the attacks, claimed the four Iraqi attackers staked out the hotels for a month before donning explosives belts and detonating them minutes apart.
It said the bombings were carried out in response to "the conspiracy against the Sunnis," referring to the Muslim Arab group favoured under Saddam Hussein's government and now believed to form the core of the Iraqi fighters.