habían achacado
-they/you had attributed
Antecopretérito para el sujeto ellos/ellas/ustedes del verbo achacar.

achacar

Buscaron a sus amigos, que habían achacado su desaparición al hecho de haber pedido prestado dinero y no tener con qué devolverlo.
His friends were looked up, and they put his disappearance down to the fact that he had borrowed some money and could not pay it back.
Palabra del día
la leña