Ana Estevez says that it wasn’t until she filed for divorce from her husband of eight years, Aramazd Andressian Sr., that she learned he had been lying to her for years. Estevez, mom to 5-year-old Aramazd “Piqui” Andressian Jr., says her husband would typically call daily to speak to their son, but after not hearing from him for a few days, she called his place of employment to check on him.

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“I requested to speak with the campus director. And his response was, ‘Who?’ And I said, ‘Ara.’ And he says, ‘I know Ara.’ He says, ‘Ara and I used to work together in West Covina, but that was several years ago.’ He says, ‘Ara doesn’t work here.’ And that’s how I found out he had lied to me and my son for over four years,” Estevez tells Dr. Phil in an exclusive interview airing Tuesday.

Estevez says after learning that her husband had been deceiving her about working, she decided to hire a private investigator.

“I needed to know what he was doing with my son,” Estevez says.

WATCH: Woman Claims Ex-Husband Who Killed Their Son Made The Child Lie During Custody Battle

In the video above, hear what she learned from the private investigator.

Estevez and Andressian Sr. soon became entangled in a bitter custody battle. On April 21, 2017after a trip to Disneyland with his son, Andressian Sr. murdered little Piqui. On Tuesday’s episode of Dr. Phil, hear more of Estevez’s story, including how she says she believes she was let down by the court system. And, learn about her son’s final hours and their last conversation. Check here to see where you can watch.

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Ana Estevez Describes What Happened When She Attempted To Get A Restraining Order Against Ex Aramazd Andressian Sr.