JAKARTA, Indonesia (CNN) -- A bomb discovered in an 18th floor room of a luxury hotel in Indonesia was armed and timed to detonate before two other fatal bombs exploded far below, police said Friday.
Passersby in front of the Ritz-Carlton hotel in Jakarta, Indonesia, on Thursday.
The twin blasts July 17 at Jakarta's JW Marriott and Ritz-Carlton hotels killed nine people -- including at least two presumed suicide bombers -- and wounded more than 50.
Two days before the explosions, the suicide bombers checked into room 1808 of the Marriott, where the unexploded bomb was found and defused, police said.
It was timed to detonate on the upper floor before the first blast tore through the Marriott's lobby area at 7:47 a.m., said Ketut Untung Yoga of the national police. The second bomb went off at the adjacent Ritz-Carlton 10 minutes later.
Earlier media reports said police had recovered a laptop they believed belonged to the bombers in a room at the Ritz-Carlton. But police have not confirmed the claim.
However, police said they found a black laptop bag in Room 1808 that contained the malfunctioning bomb.
No one has claimed responsibility for the bombings but Indonesian investigators are looking into a possible connection between the attacks and Noordin M. Top, the suspected leader of a small splinter group of the militant Jemaah Islamiyah.
The group, said to have links to Osama bin Laden's al Qaeda terrorist network, is blamed for the 2002 Bali bomb attacks in which 202 people, mainly foreign tourists, were killed.
It was also said to be behind an attack on the Australian embassy in Jakarta in which nine people died in 2004 and a 2004 attack on the same Marriott hotel in killed eight.