Brown's body was covered in bruises and scars at the time of her death, the Fulton County Medical Examiner's office said
Credit: Tiffany Rose/WireImage

Bobbi Kristina Brown‘s boyfriend Nick Gordon has “always maintained that he didn’t kill” – and the Fulton County Medical Examiner’s autopsy report released Friday “backs up his claim,” a source close to Gordon tells PEOPLE.

According to the report, Brown’s body showed signs of acute injury; depressions in her skull; bruises on her arms and thighs; and dozens of “well-healed scars on the head and neck, torso, and extremities.” And a toxicology report showed marijuana, alcohol, “a cocaine-related substance,” sedative and anti-anxiety medications and morphine were found in her system.

The source suggests the findings contradict claims in a wrongful death suit against Gordon, 20. Brown’s family alleges she “died due to a violent altercation” with Gordon and that he “injected her with a toxic mixture” – allegations Gordon has previously denied.)

“She had drugs in her system, and this wasn’t a cocktail,” says the source. “Nick didn’t inject drugs into her.”

The source continues: “Sadly, Bobbi Kristina used drugs for a long time, and she drowned in her bathtub. It’s a tragedy, but Nick didn’t kill her.”

Brown family members see the medical examiner’s release differently. “While this action is unsettling, we will continue in our efforts in the civil lawsuit and the criminal investigation,” said her father Bobby Brown’s lawyer, Christopher Brown, in a statement to PEOPLE. The message echoed his sentiment from last year, when the attorney told PEOPLE, “In regards to the civil litigation, we believe we know who harmed Bobbi Kristina Brown and his name is Nick Gordon.”

As for Gordon’s mindset on what would have been Brown’s 23rd birthday, Gordon – who was raised as Houston’s son, but never officially adopted – is “doing as well as can be expected,” says the source. “He’s glad that the autopsy report shows that he didn’t do it, but at the end of the day, he loved Bobbi Kristina and misses her.”

According to the source, “He has not gotten to mourn her loss like he wanted to, because he’s been too busy defending himself from the claims that he killed her. He misses Bobbi Kristina, and he is still dealing with that.”

Earlier Friday, Gordon posted about Brown on Facebook, writing, “”Happy Birthday baby girl!!”

Meanwhile, her father Bobby Brown expressed concern over the release, telling PEOPLE in part, “For news affiliates to seek and obtain my daughter’s autopsy report, before anyone has been brought to justice for her death is mind blowing to me. Please pray for my family.”

Brown was found unresponsive in her bathtub on Jan. 21, 2015. She spent months in the hospital, a rehabilitation center and hospice care until she died on July 26.