PHILADELPHIA (WPVI) -- Action News is looking into one mother's claims her daughter was killed at the hands of a Philadelphia police officer in a case that was ruled a suicide in 2012.In a letter leaked to 6abc, the Police Advisory Commission questioned if crucial details of past physical abuse and other evidence was missing in the investigation into the death of Erica Koschman.Koschman, who was just 29-years old at the time, was Sharon Koschman's only daughter.She says Erica always saw the best in people, including her fiancee, a Philadelphia police officer."She loved him, and he was broke, and she was going to fix him," said Sharon Koschman.But Koschman says the one-and-a-half year relationship was on rocky ground. Her daughter, she tells us, phoned her on Jan. 11, 2012, and said her car was packed with her belongings. She was coming home after her fiancee asked her to leave."She was like no, no, no, mom it's fine. I'll see you at the house when you are done with work," said Sharon Koschman. "Nineteen minutes later, I get a phone call she's dead."The Philadelphia EMS report documents a female with a gunshot wound to the head and copious amounts of blood on the flood next to the body.The bedroom was declared a crime scene and the investigation was turned over to homicide."She didn't shoot herself, period. It wasn't suicide," said Sharon Koschman.The medical examiner's report details conflicting accounts of what transpired prior to the terminal event.Koschman, it says, told them her daughter's relationship was volatile, including past issues with him allegedly putting his hands on her. There were also allegations Erica was abusing prescriptions. The toxicology report found low levels of anti-anxiety medications in her system.The medical examiner ruled Erica Koschman's death was a suicide.Philadelphia Police Advisory Commission Executive Director Kelvyn Anderson sent the letter to former Police Commissioner Charles Ramsey requesting that he reopen the case."It's our job in this instance to try and follow up on those details, and try to shed some light on what was done properly and what was not done properly," said Anderson.The basis included a history of alleged domestic violence as evidenced in a hospital emergency room report.A month earlier, Erica Koschman, who had bruising on her legs, told nurses she was being abused by her boyfriend, but said she was afraid to call police because her boyfriend is a police officer. After police were called, she said it was an accident, and did not want to press charges.Investigative Reporter Wendy Saltzman asked Anderson if he believed this case was handled differently because a police officer was there on the scene."That's an important question. We don't have answers to that yet," Anderson responded.And possibly most baffling, according to Anderson, was why a gun residue test was never performed on the officer."That's very unusual," said Dr. Gregory McDonald.Dr. McDonald is a medical examiner and the Chair of Forensic Medicine at the Philadelphia College of Osteopathic Medicine."It's consistent with a suicide, but it's also consistent with maybe someone else pulling the trigger as well," said Dr. McDonald.But, it's what wasn't mentioned on the report that really caught his eye."There was no mention of what we would call blood spatter on the right hand," said McDonald.McDonald says blowback from the blast including blood would have been on Erica's hand if she had shot the .40 caliber handgun at close range."I think I would maybe leave the door open and call the manner of death undetermined," said McDonald.So what does that trail of evidence, or lack thereof, at the crime scene say about the case? The officer declined our requests for an interview, so we asked Philadelphia police."I think we went above and beyond what's normally done on a day to day because this was a police officer," said Lt. John Stanford.Stanford tells Action News the Koschman case has actually been investigated by the department four separate times. And all four times, he says it was ruled a suicide.As for that report of domestic violence?"This is a death investigation. The domestic violence that happened previously, that would be relevant if this was determined to be a homicide investigation," said Stanford.Police also defended the failure to test the officer's hands for gun residue."To be very honest, when you do that type of test if it comes back negative, which it probably would have, you're actually giving that person a defense," said Stanford.The Philadelphia Medical Examiner's Office told Action News if new information came to light, they could amend the death certificate.The Police Advisory Commission has launched their own investigation, and is conducting interviews with the officers involved. But so far, the Philadelphia police says it has no plans to reopen the Koschman case.