Imprisoned by the Republican authorities at the start of the Spanish Civil War, he was later killed—along with a number of other political prisoners—by anarchist militiamen in the Cárcel Modelo massacre.

[8] His parents were José Rico García-Lañón—a well-to-do member of the Asturian bourgeoisie and later a republican mayor of Valdés[9]—and Dolores Avello Suárez.

[17] Lerroux described Rico Avello as "a man of 'good will', 'noble character' and 'good intentions'", but also as "'until yesterday a traditional cacique and now the guardian of electoral virtue'", and noted that his appointment was made as a result of President Acala Zamora's influence.

[19] In early 1936, there existed speculation that President Niceto Alcalá-Zamora was on the verge of dismissing Prime Minister Manuel Azaña and appointing Rico Avello in his place—at the head of a 'more responsible left Republican government'.

[20] On 14 August 1936, Rico Avello and his son Carlos were arrested by agents of the Milicia Populare de Investigación—a highly politicised and socialist controlled Civil War police brigade[21][22] —and imprisoned in the Cárcel Modelo.