Factbox: U.N.-backed commission leading Guatemala graft purge

GUATEMALA CITY (Reuters) - Guatemala's President Otto Perez on Sunday refused to resign after he was implicated in a corruption probe led by a U.N.-backed body that has plunged the political establishment into deep crisis ahead of a presidential election in September.

Following are details about the International Commission against Impunity in Guatemala (CICIG), which was formed in late 2006 to help the Guatemalan state investigate crimes by illegal armed groups in the violent Central American country:

* The CICIG is currently led by former Colombian state prosecutor Ivan Velasquez, 60, who won renown for investigating links between politicians and paramilitaries in his homeland and took the helm of the body in Guatemala in late 2013.

* The body spearheaded a probe into a fraud at Guatemala's customs office known as la Linea, after a telephone hotline used in the scandal. The investigation and those that followed it sent shockwaves through Guatemalan politics, and helped fuel massive demonstrations against Perez's government.

* Several ministers were sacked or resigned over La Linea, and Velasquez has said it is clear Perez was involved.

* The CICIG moved against Perez following months of investigations that centered on his former Vice President Roxana Baldetti and one of her top aides, who is now fugitive.

* Working with the CICIG, Guatemala's Attorney General Thelma Aldana had Baldetti arrested on Aug. 21 and promptly sought the impeachment of Perez, a retired general who served in Guatemala's bloody 1960-1996 Civil War.

* Findings against Baldetti and Perez were taken from some 89,000 telephone taps, almost 6,000 emails and 17 raids.

* The mandate of the CICIG was set to expire in September, but was extended by the Guatemalan government in April for two years amid political, popular and international pressure, notably from the United States.

* In a separate probe, the CICIG accused the running mate of the favorite to win September's presidential election of graft, eroding the front-runner's lead and casting doubt on the result.

* Another CICIG investigation into corruption at Guatemala's social security institute sparked the arrest of more than a dozen officials including the central bank governor.

* The CICIG's success has prompted calls for the creation of similar bodies in neighboring countries grappling with organized crime and drug violence, such as Honduras, El Salvador and Mexico.

(Reporting by Enrique Andres Pretel)