[2][3] Beginning in the 1990s, crime committed by street gangs became a major problem in El Salvador after many Salvadoran refugees from the country's civil war began to be deported from the United States.

[2] At 7:30 p.m. on 20 June 2010, members of the Barrio 18 Revolucionarios clique[6] shot at a minibus operated by bus route 47 in Mejicanos, killing the driver and a passenger in the process.

[10] In a direct response to the Mejicanos massacre, the Legislative Assembly of El Salvador passed the "Law Prohibiting Maras, Gangs, Groups, Associations, and Organizations of Criminal Nature", which was drafted by Funes, on 1 September.

Both MS-13 and Barrio 18 organized a public transportation strike in an attempt to force the Legislative Assembly to repeal the law to no avail.

[2] On 21 June 2010, the National Civil Police announced the arrests of eight gang members who were suspected of being involved in the massacre, three of whom were minors.

[1] On 8 November 2011, Juan Antonio Borja Alvarado and Éver Alexis Martínez were sentenced to 66 years imprisonment for their role in the massacre.

[5] On 9 July 2021, the National Civil Police arrested four more gang members supposedly involved in the Mejicanos massacre.

Salvadoran authorities believed that this attack was committed in order to prove the gang's worthiness to Los Zetas, a Mexican paramilitary group and drug cartel which was at the time expanding its operations into El Salvador.