A soldier stands guard outside the house at the end of the tunnel through which Mexican drug lord Joaquin "El Chapo" Guzman could have escaped from the Altiplano prison, in Almoloya de Juarez, Mexico, on July 12, 2015
Mexico City (AFP) - Mexican President Enrique Pena Nieto's battle against drug cartels took a massive hit with drug lord Joaquin "El Chapo" Guzman's escape, stripping him of his security strategy's biggest trophy.
Pena Nieto's nearly three years in office have been marked by a remarkable number of arrests of the country's most notorious drug kingpins.
The captures of Sinaloa cartel boss Guzman and the chiefs of the Zetas, Knights Templar and Gulf criminal groups earned praise from the United States.
But Guzman's second prison break in 14 years has undermined these achievements, while reviving accusations of corruption and impunity that have shadowed the government's efforts.
US prosecutors had wanted to extradite Guzman but Mexico's government insisted on putting him on trial first.
"In the best case, this escape is embarrassing," said Alejandro Hope, a former Mexican intelligence agency official.
"It dents the image of effectiveness that (the government) had projected and it forces a rethink of that narrative that we are doing well in terms of security," said Hope, editor of the security analysis website ElDailyPost.com.
- President 'deeply troubled' -
Following Guzman's arrest in February 2014, Pena Nieto himself had acknowledged in an interview with the US channel Univision that it would be "truly unforgivable" if he escaped from prison again.
Speaking during a visit to Paris on Sunday, a "deeply troubled" Pena Nieto demanded an investigation on whether guards helped the inmate flee through a secretly built tunnel under his cell.
Prosecutors interrogated some 30 officials from the Altiplano prison in central Mexico State.
Guzman and his Sinaloa cartel have given headaches to the last three Mexican presidents.
It was during president Vicente Fox's 2000-2006 tenure that Guzman escaped by hiding a laundry cart in a maximum-security prison in western Jalisco state in 2001.
His successor, fellow conservative Felipe Calderon, is notorious for launching the militarized battle against cartels in 2006, which led to an escalation of the drug war that has killed tens of thousands of people.
Then Pena Nieto came along in December 2012, and less than two years into his presidency, his security forces caught the biggest fish of them all.
With Guzman's capture, Pena Nieto signaled that his administration would go after the top leaders of the country's criminal groups.
Guzman was sent to what was until now considered the country's most impenetrable penitentiaries, the Altiplano prison some 90 kilometers (55 miles) west of the capital.
The attorney general at the time, Jesus Murillo Karam, said Mexico would prosecute Guzman first before authorities could consider a US extradition bid.
"This leads to a big problem with the US government because they asked (for an extradition) and the Mexican government did not deliver him," said Raul Benitez Manaut, security expert at the National Autonomous University of Mexico.
Instead of putting Guzman on trial, Mexican authorities were yet again scrambling to find the country's most powerful drug lord after he fled through a 1.5-kilometer tunnel under his cell's shower.
"There certainly was corruption inside and outside the prison," said Benitez Manaut.
- Trump card -
The escape is another piece of bad news for a president whose fortunes began to take a turn for the worse in the middle of last year.
Once praised internationally for his sweeping reforms in the energy sector, the tax system and education, Pena Nieto's popularity nosedived after local police in the southern city of Iguala seized 43 college students and delivered them to a drug gang that allegedly slaughtered them all.
Security analyst Javier Oliva predicted that the Guzman scandal could become a US presidential election topic given the anti-Mexican stance taken by billionaire tycoon Donald Trump.
"What will Donald Trump say? This will be fuel for his conservative candidacy," Oliva said, referring to Trump's remarks last month that Mexican migrants were bringing crime north of the border.
Trump obliged hours later, writing on Twitter: "Mexico's biggest drug lord escapes from jail. Unbelievable corruption and USA is paying the price. I told you so!"