Five suspects have been arrested in connection with the May 15 bombing that targeted former Colombian Interior Minister Fernando Londoño, Attorney General Eduardo Montealegre said Tuesday.

The suspects "are persons who do not belong to the FARC," Montealegre said, adding that investigators were still looking at the possibility that the guerrilla group may have been involved in the attack.

Two people were killed and more than 30 others injured when the bomb went off as Londoño's vehicle was going through a busy intersection in the northern section of Bogota, near the financial district.

"Obviously, one of our main working theories is that the FARC may have eventually been behind the attack," Montealegre told Colombian radio networks.

The Revolutionary Armed Forces of Colombia, or FARC, is the country's oldest and largest leftist guerrilla group.

The suspects belonged to El Parche de la Ley, a gang based in the southwestern city of Cali, Defense Minister Juan Carlos Pinzon said during a joint press conference with National Police director Gen. Jose Roberto Leon and Montealegre.

The evidence gathered so far "does not allow us to clearly establish who the intellectual authors are," Pinzon said.

"However, we cannot rule out the authorship of the FARC and, particularly, the Teofilo Forero (Mobile) Column in this incident," the defense minister said.

There have been instances in the past where the FARC hired gangs or criminals to carry out attacks, Pinzon said.

Londoño, who served as interior minister from 2002 to 2004 in the administration of Alvaro Uribe, said in a press conference in May that the FARC staged the attack with a limpet bomb.

The bomb destroyed a bus and several other vehicles, and it damaged nearby buildings and businesses.

Londoño, who left office amid a corruption scandal involving the irregular purchase of millions of shares of a state enterprise, went to work for Bogota's RadioSuper network, hosting a news show.

Some officials blamed the attack on the FARC from the start, but others, including Montealegre, said the guerrilla group's involvement was just a theory.

President Juan Manuel Santos has said on several occasions that it was not clear who carried out the bombing.

"We have managed to identify the material authors, members of a criminal gang, and what we want to establish is precisely who provided the bomb, the technology, who was really behind this attack," Montealegre to Caracol Radio.

The suspects - a minor and four adults - were arrested during a raid in Cali.

The minor is apparently the individual seen on videos recorded by security cameras wearing a wig and placing the bomb on Londoño's vehicle.

A man who was serving a 34-year prison sentence for kidnapping and was released due to health problems is among the other suspects, Leon said. EFE