Watch | Mexican drug lord digs tunnel, escapes from prison

Mexican security forces hunted early on Monday for top drug lord Joaquin "El Chapo" Guzman - the world's richest and most powerful trafficker before his arrest last year - as authorities investigated whether he had inside help to escape prison through a tunnel under his cell's shower. It was the second time in 14 years that Guzman, the head of the powerful Sinaloa drug cartel, managed to flee a maximum-security prison, dealing an embarrassing setback to President Enrique Pena Nieto. Guzman was recaptured in 2014 after he escaped hidden inside a laundry basket.