Spanish police have detained a 24-year-old man suspected of shooting Colombian drug lord Leonidas Vargas dead in January in his Madrid hospital bed, authorities said Wednesday.

The 24-year-old Colombian, identified as Jonathan Andres O., was detained at Madrid's Barajas airport on Sunday after he arrived in the Spanish capital on a flight from Cali in Colombia, police said.

Police suspect he is the man who walked into the Madrid hospital room where Vargas was being treated for a pulmonary problem on January 8 and pumped four bullets into the 60-year-old while another man kept watch outside the door.

Six days later, gunmen in Colombia also murdered Vargas' brother, Fabio Vargas, along with actress and former beauty queen, Liliana Lozano.

In March Spanish police arrested three Colombians and a Romanian in Madrid who are suspected of involvement in Vargas' murder.

Spanish police arrested Vargas in July 2006 in connection with a shipment of 500 kilogrammes (1,100 pounds) of cocaine. He was subsequently released on bail as the investigation continued pending a possible trial.

At the time of his arrest, Colombia was offering a reward of five million dollars for his capture.

A Colombian court sentenced him to 19 years in jail in 1995, but he was released in 2002.

Investigators considered Vargas a key figure in the Colombian drugs trade, linked to the Medellin cartel.

Spain is Europe's main entry point for cocaine from South America, mostly from Colombia, the world's top producer of the drug.