Toni Braxton's niece died of a heroin overdose and fentanyl intoxication.

Toni Braxton

Toni Braxton

Lauren Braxton passed away in April aged 24, which left the 51-year-old singer "heartbroken", and the medical examiner's office in Maryland has told E! News the autopsy results, but the manner is still undetermined.

Lauren - the daughter of Toni's younger brother Michael Conrad Braxton Jr. - was said to be found unresponsive by paramedics in April, and she was pronounced dead soon after.

Toni wrote on Instagram at the time: "R.I.P to my amazing niece Lauren 'Lo Lo' Braxton ... I'm still in disbelief and so very heartbroken ... Love you ... always auntie 'Te Te.' (sic)"

Lauren's other aunties Trina and Traci Braxton also paid tribute to her.

Trina wrote: "God sent me another angel! Rest in Heaven Lauren 'LoLo' Braxton (sic)"

Traci said: "LoLo was more than my niece, she was my daughter; and I, my son and husband are truly heartbroken over her passing."

Lauren's auntie Tamar Braxton previously admitted she didn't "have time" to go to her funeral, because she was "still drained" from her niece's passing.

She said: "I've been M.I.A. because I just cannot bring myself to post about my niece. Like, I just can't do it. But what I did want to say is I want to thank everyone for sending their condolences.

"I don't want my sisters or my family to get upset with me, but the things that have been going on -- this is the first time that anybody in my family has passed. Nobody tell you about going to the damn funeral. I don't have time going to the funeral. I'm still drained from that ... It's a lot. Everything happens in God's divine order and you've got to respect it and praise him anyway."