From Bloomberg, April 22 (link added):

Former Colombian Senator Mario Uribe asked Costa Rica for political asylum after a prosecutor ordered his arrest for alleged ties to paramilitary groups, El Tiempo newspaper said, citing his attorney, Jose del Carmen Ortega.

Uribe, a cousin of Colombian President Alvaro Uribe, went to the Costa Rican embassy in Bogota today on the grounds that he doesn't have adequate procedural guarantees in Colombia, the daily newspaper said, citing a source it didn't name. He has repeatedly denied links to paramilitary death squads.

Mario Uribe's arrest would bring to 33 the number of lawmakers detained in a growing scandal over alleged ties to paramilitary groups, Bogota-based El Tiempo said.

More details from BBC, April 23:

Mario Uribe Escobar, who stepped down as a senator last October, is accused of criminal conspiracy.

He went to the Costa Rican embassy in Bogota seeking asylum, but his request has been turned down.

Mario Uribe, one of the most prominent figures arrested over alleged paramilitary links, denies wrongdoing.

A jailed former paramilitary leader, Salvatore Mancuso, has alleged that he met Mario Uribe several times and was asked by him to support his senate campaign in 2002.

Former paramilitary commanders have also testified that militias reached agreement with him to help him take over farmland.

A statement from the prosecutor's office accused Mario Uribe of entering into "agreements to promote illegal armed groups," the Associated Press news agency said.