Sometimes he told customers he needed to add himself temporarily in order to "test" the system; other times he just added himself without even telling them.
According to the Department of Justice, Aviles even "took note of which homes had attractive women".
He admitted repeatedly logging into these customers' accounts in order to view their footage for sexual gratification. He confessed to watching numerous videos of naked women and couples engaging in sexual activity inside their homes.
Over a four and a half year period, Aviles admitted secretly accessing roughly 200 customer accounts more than 9,600 times, without their consent.
"This defendant, entrusted with safeguarding customers' homes, instead intruded on their most intimate moments," Acting U.S. Attorney Prerak Shah said. "We are glad to hold him accountable for this disgusting betrayal of trust."
"The defendant used his position of employment to illegally breach the privacy of numerous people," FBI Dallas Special Agent in Charge Matthew J. DeSarno added, reminding the public to practice "cyber hygiene" with all connected devices, by reviewing authorized users and routinely changing passwords.
Aviles now faces up to five years in federal prison when sentenced.
He was fired by ADT last April; the company now faces lawsuits from the customers who were spied on.