Police in Mexico have arrested the father-in-law of the country's most wanted man, the drug boss Joaquin 'El Chapo' Guzman.

BBC: Mexico arrests Joaquin 'El Chapo' Guzman's father-in-law

But Jack Riley says that Guzman, whose nickname El Chapo means "shorty" in Spanish, is more ruthless than the legendary gangster.

BBC: Chicago names Joaquin Guzman public enemy No. 1

It is estimated that El Chapo controls at least 60, 000 square km (23, 000 square miles) of rugged mountains in Sinaloa and Durango.

FORBES: Mexican Billionaire Drug Kingpin "El Chapo" Guzman Named Chicago's Public Enemy No. 1