The Tulsa, Oklahoma Office of the Chief Medical Examiner said that Lambert (pictured in 1999) died from a self-inflicted shotgun wound to the head. Toxicology tests are pending. Though the office had no more information at this time, the National Enquirer alleges Lambert suffered depression surrounding the anniversary of his mother's death and descended into a drug binge prior to his suicide.
"It's a shame that such a talented human being would do this with his life," his grandmother Joni Richardson tells PEOPLE. "He had all the opportunities in the world and we just can't understand it."
In reports from a not-yet-online National Enquirer piece, Lambert's grandmother said, "Tyler wanted to be with his mother. His father Lanny (Lambert, Plato's ex-husband) is devastated."
Dana Plato committed suicide with prescription pills on May 8, 1999. She was 36 years old. In 2006, a 21-year-old Lambert filed a $20,000 wrongful death lawsuit against Plato's former fiance, claiming he contributed to Plato's death by "not giving immediate medical assistance or contacting medical personnel," according to court documents.