Honduran authorities have arrested nine people in connection with last week's massacre of 28 bus passengers, President Ricardo Maduro has said.
The bus was carrying mostly women and children
Mr Maduro said all indications were that the notorious Mara Salvatrucha gang was responsible for the killings.
The bus was driving through a busy district in Chamalecon, in northern Honduras, when it was surrounded by gunmen and sprayed with automatic fire.
Six of those who were killed in the attack were children.
Mr Maduro told reporters on Monday that he was satisfied with the police's handling of the case and added that he would demand life imprisonment for those found guilty of the massacre.
The police investigation into the attack has centred on suspected gang member Alexis Ramirez, 23, who was arrested shortly after it took place.
On Sunday, Security Minister Oscar Alvarez said Ramirez had been identified by survivors, who saw him board the bus briefly to fire on passengers at close range.
The gunmen left behind a note saying they represented a guerrilla group, the Cinchonero People's Liberation Movement, opposed to the reintroduction of the death penalty in Honduras.
However, the group in question has not been active since the 1980s and is thought to be defunct.
The attackers' note also challenged a number of leading politicians who have come out strongly against organised crime - particularly the president of Congress, Porfirio Lobo.
Mr Lobo, a potential candidate in next year's presidential election, has been a strong advocate of the death penalty for serious crimes.
The Mara Salvatrucha is one of a number of Los Angeles-style youth gangs that sprang up in the region after their members were deported from the US in the 1990s.
The founders of the gangs were typically Central American youngsters whose families had fled to the US to escape civil war.
After peace accords were signed, they were sent back to their countries and took the street-gang culture with them.
The Mara Salvatrucha now has an estimated 25,000 members in Honduras, neighbouring El Salvador and other Central American nations.