ATLANTA, United States (AP) — An autopsy will be needed to evaluate what led to the death of Bobbi Kristina Brown, daughter of singer Whitney Houston, authorities said Monday, the day after her death.

In a statement Monday morning, the Fulton County Medical Examiner’s Office says the time that elapsed from when she was found unresponsive in January until her death Sunday will “complicate” its effort to reconstruct events.

“Interpretation of autopsy findings and other information will also be challenging,” the medical examiner’s office said in the statement. “However, an autopsy could be helpful to address questions which may arise about the cause of her unresponsiveness and eventual death.”

Bobbi Kristina died Sunday at Peachtree Christian Hospice in Duluth, Georgia, about six months after she was found January 31, face-down and unresponsive in a bathtub in her suburban Atlanta townhome. She was 22.

A police report described it as a drowning.

Bobbi Kristina was the only child of Houston and R&B singer Bobby Brown.

“Bobbi Kristina Brown passed away July, 26 2015, surrounded by her family. She is finally at peace in the arms of God. We want to again thank everyone for their tremendous amount of love and support during these last few months,” Kristen Foster, a representative for the Houston family said Sunday.

She had been hospitalised for months in Atlanta — eventually being placed in hospice care — after being found in a manner grimly similar to the way her megastar mother died three years earlier.

Nick Gordon, who shared her townhome with her, said at the time it seemed Bobbi Kristina wasn’t breathing and lacked a pulse before help arrived.

“The Roswell Police Department continues its investigation into the circumstances preceding and surrounding the time of the original incident leading to her death,” the medical examiner said in Monday morning’s statement.

The medical examiner did not release a timeframe for the autopsy, but said additional lab testing might take several weeks.

Born and raised in the shadow of fame and litigation, shattered by the loss of her mother, Bobbi Kristina was overwhelmed by the achievements and demons of others before she could begin to figure out who she was.

Bobbi Kristina — the sole heir of her mother’s estate — did have dreams.

She identified herself on Twitter as “Daughter of Queen WH,” ”Entertainer/Actress” with William Morris & Co, and “LAST of a dying breed.” She told Oprah Winfrey shortly after her mother’s death in 2012 that she wanted to carry on her mother’s legacy by singing, acting and dancing. But her career never took off.

She became a social media sensation, sending more than 11,000 tweets and attracting 164,000 followers.

As the news of her death spread across social media, several celebrities tweeted their condolences.

Grammy-winning performer Missy Elliot tweeted, “My heart is truly heavy. May u rest in peace with your mommy #BobbiKristina sending prayers 2 the Brown/Houston family.”

“Empire” star Taraji P Henson tweeted, “Rest in heaven.”

“RIP #BobbiKristina My deepest sympathies 2 your father #BobbyBrown n your GrandMa #CissyHouston We will miss ya 4sho darling 😉 Actress Vivica A Fox said on Twitter.

And Winfrey tweeted, “Peace at Last!”

Whitney Houston, known as “America’s Sweetheart,” was an impossible act to follow.

The late singer sold more than 50 million records in the United States alone during her career. Her voice, an ideal blend of power, grace and beauty, made classics out of songs like “Saving All My Love For You,” ”I Will Always Love You” and “The Greatest Love of All.” She earned six Grammys and starred in the films “The Bodyguard” and “The Preacher’s Wife.”

Bobby Brown, who had a bad-boy image, also became a huge star, selling platinum records with New Edition and going solo before drugs and legal woes derailed his career.

Bobbi Kristina appeared alongside both parents in 2005 on the Bravo reality show “Being Bobby Brown,” which captured her parents fighting, swearing and appearing in court. The Hollywood Reporter said it revealed that Brown was “even more vulgar than the tabloids suggest”, and managed “to rob Houston of any last shreds of dignity”.

After their divorce in 2007, Houston kept custody of Bobbi Kristina and raised her alongside Gordon, an orphan three years older than her daughter. Houston brought Gordon into her family, and while she never formally adopted him or included him in the will, both teenagers called her “mom”.

The threesome’s tight bond was shattered when Houston’s assistant found the singer’s lifeless body face-down in a foot of water in her bathtub at the Beverly Hilton Hotel just before the Grammy Awards in 2012. Authorities found prescription drugs in the suite, and evidence of heart disease and cocaine in her body, but determined her death was an accidental drowning.

Bobbi Kristina, then 18, was at the hotel and became so hysterical she had to be hospitalised. “She wasn’t only a mother, she was a best friend,” she told Winfrey.

She and Gordon then went public with their romance, posting defiant messages online after the tabloids accused them of incest.

Relations between Gordon and some other relatives soured over the past year after Bobbi Kristina was hospitalised. A protective order barred him from being within 200 feet of Pat Houston, Bobbi Kristina’s aunt. A feud erupted over whether Gordon could visit Bobbi Kristina while she stayed in the hospital.

On June 24, Bobbi Kristina’s court-appointed representative sued Gordon, accusing him of misrepresenting his relationship with Bobbi Kristina. The complaint accused him of being violent toward her and taking more than US$11,000 from her account while she was in a medically induced coma.

The lawsuit also accused Gordon of assault, battery, intentional infliction of emotional distress, unjust enrichment, and conversion.

Fulton County District Attorney Paul Howard said he and his office are interested in reviewing the investigative file to determine whether any charges will be filed.

Bobbi Kristina was fabulously wealthy for a teenager, but her money was in a spendthrift trust, designed to keep creditors and predators from taking advantage of people who can’t manage their money. Bobbi Kristina’s grandmother, Cissy Houston, and aunt, Pat Houston, eventually took over control of the trust and then took Bobbi Kristina to court to protect the estate.

The size of Houston’s estate is a privately held secret.

In May, a judge appointed Bobby Brown and Pat Houston as co-guardians of Bobbi Kristina, giving them joint responsibility in decisions related to her care and medical needs. Lawyer Bedelia Hargrove was appointed conservator to oversee Bobbi Kristina’s assets, including her rights and legal claims.

By January 2014, the young couple who grew up as brother and sister were sharing a townhome and calling themselves husband and wife.

They posted images of their hands wearing wedding rings, with the caption “#HappilyMarried. So #InLove. If you didn’t get it the first time that is.” They got identical “WH” tattoos with flying doves on their wrists, and Gordon added a large portrait of Houston’s face on his arm.

Their marriage announcement troubled Pat Houston, who obtained a restraining order against Gordon two months later.