Gypsy Rose Blanchard says she believes her former fiancé and baby daddy, Ken Urker, died from an apparent overdose … telling TMZ a substance was found at the scene.

Gypsy tells TMZ … the belief is Ken overdosed because an unidentified substance was discovered where he died, though she says she does not know what the substance was.

She tells us she also doesn’t know whether the apparent overdose was intentional or accidental. PEOPLE was first to report Gypsy suspecting he died from an overdose.

Gypsy adds Ken did not have a drug problem and says she had never seen him partake in drugs or other substances. She remembers him as a responsible person who was intentional about being a father and partner.

We broke the story … Ken was found dead inside a home in Louisiana, on what would have been his 34th birthday. His death remains under investigation.

As we first reported … Gypsy spoke out following Ken’s sudden death Thursday, calling him an “amazing father” and saying he would “forever be my soulmate and my red string.”

She also said Ken had endured intense public scrutiny and cyberbullying, which she believes had a profound impact on him.

Gypsy and Ken met through a pen pal program while she was serving time in prison for her role in her mother Dee Dee Blanchard’s death.

Ken proposed during a prison visit in 2018, though they later split. Gypsy went on to marry Ryan Anderson before the pair separated, and she eventually rekindled her relationship with Ken after her release from prison.