BOGOTA, Colombia (CNN) -- Colombian police have arrested six gang members in connection with the May assassination attempt on a former minister, police said Tuesday.

Fernando Londono, a former minister of the interior and justice, survived the May 15 bombing, which killed two of his security team and injured nearly 40 others.

Security cameras in Bogota captured someone throwing a package at the vehicle Londono was riding in and then speeding away on a waiting motorcycle.

The leftist Revolutionary Armed Forces of Colombia guerrilla group, commonly known as the FARC, was suspected immediately in the attack, but police did not make a connection to the group.

Colombian President Juan Manuel Santos called the suspects "common criminals" on his Twitter page. And while police said six arrests were made, Santos and the attorney general's office put the number at five.

Four of the arrests were made in the city of Cali, and one, of a minor, was made in Bogota, the attorney general's office said in a statement.

The minor is suspected of being the one who threw the bomb, the office said.

Londono was minister of the interior and justice from 2002 to 2004 during the administration of President Alvaro Uribe.

He was known for being outspoken against leftist rebel groups, including the FARC. Londono travels with a sizable security detail because of numerous threats against him.

Journalist Fernando Ramos contributed to this report.