GUATEMALA CITY, (Reuters) – Guatemalan police have  arrested a street gang leader on suspicion of organizing the  murders of dozens of bus drivers, part of a wave of attacks on  the capital’s public transport system.

Police say 21-year-old Axel Ramirez, alias “El Smaily”  (“Smiley”), belongs to the “Mara 18” gang and ordered more than  20 shootings of bus drivers and fare collectors for not paying  extortionists.

Ramirez, arrested on Thursday after a shootout, had been  released from prison in December after serving about four years  for murdering a rival gang member.

“He was doing a lot of harm, not just extorting our country  but organizing murders and generating terror wherever he  lived,” Interior Minister Salvador Gandara told local radio.

Gangs have attacked more than 40 bus employees this year.  Usually the killers pull up to rickety city buses on  motorcycles and open fire, or climb aboard and shoot the  drivers.

Some 135 bus drivers were slain last year, 50 percent more  than in 2007 and more than twice the number murdered in 2006. Buses often crash after the shootings and passengers are  killed or injured in the mayhem. Some bus companies have staged  transit strikes in protest.