A police affidavit said her body was found Thursday night by officers who went to the family's apartment to check on her. She was last seen alive Wednesday.
The Journal & Courier reports police traced Sanchez's cellphone to Arkansas, where Clark County police detained him. The couple's children were with him, unharmed.
The affidavit alleges Sanchez told a relative he needed to leave town because he might have suffocated Arze-Lujan. An autopsy was scheduled for Saturday.