Bruce Pardo was supposed to have been watching the boy when the accident occurred, his mother told Mrs Pardo.
The revelation devastated Mrs Pardo - who had hoped to have a child with him - and she told her husband she wanted a divorce.
She wanted his child." After Mrs Pardo moved out, she talked less and less about her estranged husband but the two women were closer than ever.
Ms Jauregui last saw her friend four days before she died - and two days after her divorce was finalised.
"It just goes through your mind: what was she thinking at that moment when she looked in his eyes?
Bruce Pardo, 45, who had lost his wife, job and, finally, his dog, had planned to flee to Canada after the shooting spree, carried out with four semi-automatic weapons and an incendiary device, but shot himself after he was badly burned.
Ms Jauregui and her husband went on double dates with the new couple and found him charming and sweet.
The relationship progressed quickly, Ms Jauregui said, and the two were married in January 2006.The two kept in touch into adulthood and remained inseparable.Mrs Pardo would call Ms Jauregui every day on her way home from her job in El Monte as an administrative assistant at a flower-breeding company, and the two women saw each other regularly for shopping, drinks and dinners."If he didn't care about her or her mom and dad, he certainly didn't care about me.We wouldn't have made it out alive, we wouldn't have had a chance," Ms Jauregui said, mascara streaking down her cheeks from her tears.When Pardo met a new man, a tall, handsome electrical engineer, Ms Jauregui said her friend was immediately smitten.