A suspected senior member of one of Mexico's major drugs cartels has been arrested, officials say, BBC reported.
Carlos Beltran Leyva was arrested in Culiacan, capital of the northern state of Sinaloa, the public safety office said in a statement.
The arrest was made on Wednesday but only revealed late on Saturday.
Carlos Beltran Leyva, of the Beltran Leyva drugs cartel, is the brother of Arturo Beltran Leyva who was killed two weeks ago in a shoot-out with troops.
Arturo Beltran Leyva was known as "the boss of bosses" among Mexican drugs cartels.
Carlos Beltran Leyva, 40, was carrying a false driver's licence when he was arrested, the official statement said.
He later acknowledged he was Arturo Beltran Leyva's brother, it added.
He was also found to have two guns and ammunition, the statement said.
A source from the security ministry told Reuters that he had since been transported to Mexico City.
The Beltran Leyva Organisation (BLO) was formed after a split in 2008 from the notorious and powerful Sinaloa cartel headed by Joaquin "Shorty" Guzman.
The two gangs operate along Mexico's Pacific coast and analysts say they are involved in a bloody feud for control of lucrative smuggling routes into the US.
Mexican officials have previously described Carlos Beltran Leyva as a key member of the cartel, but it is unclear if he took over as chief after his brother died.
Correspondents say a third brother, Alfredo Beltran Leyva, was arrested in January 2008 and a fourth, Mario, is still at large and sought by police.
Arturo Beltran Leyva was one of Mexico's most wanted men with a $2.3m reward on his head.
He died with four alleged members of his cartel in a raid by troops on a flat in Cuernavaca, just south of Mexico City.