On July 13, 2011, Zahau was found dead at the Spreckels Mansion -- two days after Max's accidental fall. Zahau had been dating pharmaceuticals tycoon Jonah Shacknai, Dina Shacknai's ex-husband.
The San Diego County Medical Examiner determined Max fell from the second story landing while Zahau was babysitting him alone.
In the magazine, Dina Shacknai said she and her former husband agreed that Zahau would never attend Max's school functions, not take him across state lines and not babysit him alone.
She believes there is more to Max's death, telling the magazine: "It's still my job to find out what really happened to him, isn't it?"
Shacknai also said she sometimes dreams she is getting Max ready for a soccer game before waking up to the reality that he's dead.
Meanwhile, Zahau's family continues to try and prove she did not commit suicide, as the medical examiner's office ruled following an investigation.
The Zahau family tried unsuccessfully to have their own forensic scientist investigate inside the Spreckels Mansion before it was gutted and remodeled.
The issue of Phoenix Magazine with Shacknai's interview comes out next week.
Jonah Shacknai has spent the year since the tragedy establishing a foundation in his son's honor called Max in Motion.