Police treat Bobbi Kristina Brown case as criminal investigation
Bobbi Kristina Brown's funeral service was held at the St. James United Methodist Church in Atlanta (Fred Prouser/Reuters)

There were chaotic scenes at Bobbi Kristina Brown's funeral as her aunt Leolah Brown launched a shocking verbal attack on Pat Houston.

TMZ reports that as family and friends gathered for the service at St. James Methodist Church Leolah Brown unleashed her tirade saying: "'Whitney Houston will haunt Pat Houston from the grave. Pat you know you are wrong for this!"

She was swiftly escorted out of the service by movie mogul Tyler Perry, who is a close friend of the family.

Onlookers stated that the funeral had been a celebration of Bobbi Kristina's life, with Reverend Michael McQueen, the senior pastor at St James' hosting the emotional service which included prayers from the Bible, followed by tributes and then a eulogy.

However, Leolah's outburst while Pat was speaking disrupted the service. Leolah left the church to spoke with reporters outside while the funeral for her niece continued.

"It's not over. We've got evidence of who Pat really is, this is going to be a long drawn out process," said Leolah.

"Things are connected. Pat is a fraud and a phony. She is not a Houston, she's a Garland."

Paying tribute to her niece she said: "She will be remembered in our hearts forever. It's so sad that this has happened to her. I'm angry at Nick, I am angry at what happened. It was all fine until Pat started speaking."

The family have been embroiled in a bitter feud following the tragedy that left the 22-year-old in a medically induced coma for six months.

In an alarming Facebook post, Leolah Brown had alleged that the aspiring actress and her late mother were both victims of foul play.

"I never have said anything until Whitney was murdered and now my niece Bobbi Kristina!" she wrote.

The funeral arrangements were a cause of dispute between the families with MailOnline reporting that Dionne Warwick was threatening to boycott Bobbi Kristina's funeral because of a disagreement over plans drawn up by Pat Houston.

There was also speculation that Nick Gordon had pleaded with Bobby Brown to allow him to attend the funeral of his girlfriend, however he was not among the mourners.

Those in attendance at the St. James United Methodist Church in Atlanta included her father Bobby Brown and Atlanta Mayor Kasim Reed. Whitney's mother, Cissy Houston, was also seen leaving the home along with other guests who climbed into the SUVs.

Grammy award winning singer Monica and actor Michael Jai White were also among those gathered pay their last respects to Bobbi Kristina Brown.

Her hearse was escorted by a huge police motorcade and her coffin was carried into the church by four men dressed in black suits as family members arrived for the 11am service.

All guests were advised to arrive 'as early as possible' and bring a 'government-issued photo ID'. Guests were also asked not to bring their phones inside the church following fears that a photo of Bobbi Kristina in her coffin may be leaked to the press.

After the funeral, Bobbi Kristina's body will be flown to New Jersey where she will be laid to rest next to her mother and grandfather at the Fairview Cemetery in Westfield.

A memorial will also take place at the New Hope Baptist Church in Newark on Monday, where Whitney Houston sang as a child and where her funeral was held in February 2012.

While Bobbi Kristina is finally laid to rest beside her mother Whitney Houston, the controversy wages on, as the warring families prepare to go head-to-head over her $20m inheritance.