Mary Kay Letourneau Still Married to Vili Fualaau When She Died

Mary Kay Letourneau's full legal name is recorded as Mary Katherine Fualaau on her death certificate -- it's just one of the signs she and estranged husband, Vili Fualaau never completed their divorce.

According to the doc ... Letourneau's marital status was "married,' and it also shows Vili as her surviving spouse. This is interesting ... considering they legally separated back in 2017, though it's now clear they never followed through.

As we reported ... despite the separation, Vili had previously revealed Mary Kay's stage 4 cancer diagnosis when he posted a photo of himself wearing a medical mask with the caption, "Praying for a miracle." Mary Kay had been in hospice care for the last month ... and Vili was by her side much of that time.

She died July 6 at 12:01 PM at the Des Moines, Washington home where she lived for 3 years. The doc lists her cause of death as widely metastatic colorectal cancer which she was diagnosed with several years ago.

Mary Kay was cremated on July 13 in Seattle.

As you know, the former teacher was imprisoned in 1997 after pleading guilty to raping her then 6th-grade student, Vili. They eventually married in 2005, and had 2 kids together.