A 2002 review of an investigation into the death of Private Cheryl James recommended three soldiers should have been re-interviewed about what happened, the inquest into her death has heard.
The major crime review team raised concerns around the initial investigation into the death of Private Cheryl James, and the document was "a trigger" for the Surrey Police probe, Alison Foster QC said.
Ms Foster, representing the family, read extracts from the review team's report which described statements taken from people in connection with Pte James' death as "substandard".
Ms Foster said: "That was the trigger for the investigation which the police undertook."
The review also said, Ms Foster told the court, that there were a number of factors with reference to the way Pte James's body was found which should have raised questions about how she died.
These included the proximity of the weapon to the body, the position of the rifle, and an apparent lack of blood, Ms Foster said.
The review was "the springboard", Ms Foster said, for a police investigation.
A childhood friend of Private James said she became concerned about her after speaking to her on the phone a week before she was discovered with a fatal bullet wound at Deepcut in Surrey in November 1995.
Ms Baksh said Pte James had been known to cut herself in her teenage years but that it was "nothing serious".
She said: "On her arm she had little cuts. It was nothing serious ... She was just trying to deal with what she was going through."
The inquest has already heard Pte James, who was adopted, had been the victim of an alleged rape by two boys when she was 14 and she had taken an overdose of paracetamol after the suicide of her 18-year-old cousin Rob in 1992.
While in a statement to police about Pte James' death Ms Baksh said she was "certain" her friend had killed herself, she told the court: "Now, I wouldn't say I feel certain."
Earlier the inquest heard Pte James had been excited to sign up to a career in the military.
In an application to enlist, extracts of which were read to Woking Coroner's Court in Surrey, she wrote that it would give her "good career prospects" and a "chance to travel", adding that she considered it an "exciting job".
Her father Des, 66, broke down as his daughter's words were read to the court.
Ms Baksh, who said Pte James had "not always" been happy at home, was asked about a time she had referred to in her statement to police when she claimed Pte James and her brother had arrived at her house from their home with no shoes on following an argument.
It was suggested to her by a representative of the James family that this did not happen, but Ms Baksh said she would have had no reason to make it up.
A second inquest into the death of Pte James, from Llangollen in North Wales, is examining evidence suggesting she may have been sexually exploited by senior ranks shortly before her death.