  We construct Calabi-Yau threefolds defined over $\mathbb{Q}$ via quotients of
abelian threefolds, and re-verify the rigid Calabi-Yau threefolds in this
construction are modular by computing their L-series, without \cite{Dieulefait}
or \cite{GouveaYui}. We compute the intermediate Jacobians of the rigid
Calabi-Yau threefolds as complex tori, then compute a $\mathbb{Q}$-model for
the 1-torus given a $\mathbb{Q}$-structure on the rigid Calabi-Yau threefolds,
and find infinitely many examples and counterexamples for a conjecture of Yui
about the relation between the $L$-series of the rigid Calabi-Yau threefolds
and the $L$-series of their intermediate Jacobians.
