<p>More than 180 writers sign letter renewing calls for information on 12 authors detained incommunicado since 2001 crackdown on free speech by Isaias Afwerki</p><p>More than 180 writers have signed a letter to Eritrean president Isaias Afwerki calling for proof of life for 12 writers arrested in 2001.</p><p>Nobel laureates Olga Tokarczuk and JM Coetzee join prominent writers including Colm Tóibín, Elif Shafak, Isabel Allende, Ben Okri, Yann Martel, Kamila Shamsie and Tsitsi Dangarembga in signi