The Abu Sayyaf group has been blamed for the bombings, which left 30 people wounded.
The three suspects — Adzmar Abduraup, 33; Angon Asmarin, 32; and Ibnoyadin Samier, all from Tipo-Tipo, Basilan — were arrested shortly after the first blast destroyed a van along Campaner street, wounding five people.
A second explosion demolished the St. Anne’s Pension House atop a fast food outlet about half an hour later and accounted for most of the wounded.
No suspects have been arrested in the second blast.
Police said a witness saw one of the three men slip something under the van moments before the explosion. They were later nabbed in a nearby hotel where they had checked in using aliases.
They were charged with multiple attempted murder but were released last Friday after posting a property bond of P320,000 each, which is allowed for suspects who have no cash for bail, lawyer Robert Buenaventura said.
Mayor Celso Lobregat has lamented that the country does not have an anti-terrorism law, which could allow police to hold suspects without bail.
Lobregat later met with police and military officials and asked them to monitor the suspects’ movements.
Senior Superintendent Henry Losañez, city police chief, vowed to pin down the three suspects based on "strong evidence," adding an investigation is underway into their possible links to the second blast.
Earlier, Basilan Rep. Jerry Salapuddin and Anak Mindanao party-list Rep. Mujiv Hataman claimed that the three suspects were mere "fall guys."
"The real bombers may just be somewhere and laughing at us," Salapuddin was quoted as saying in reports.
Officials said the bombings might have been intended to divert a major military offensive against Abu Sayyaf chieftain Khadafy Janjalani in Maguindanao. — With AP