Before Michelle O'Connell went on a trip to Hawaii in 2009, she wrote a letter to her daughter. Michelle planned on skydiving while she was on vacation, and she wanted to document how much she loved 4-year-old Alex - just in case. "She was the best mom. She was the best aunt," says sister Jennifer Crites. "She just loved life she loved her daughter. She lived for Alexis." 24-year-old Michelle's devotion to her daughter is just one reason her family and friends insist she never would have killed herself. But there are lots of other reasons. She'd just gotten a promotion and was supposed to start her new job the next day. She told her family she was going to leave her boyfriend and was in fact packing to leave. And - just minutes before a bullet ended her life, she texted her sister that she was coming to pick up Alex. 911 call: "Please get someone to my house! My girlfriend -- I think she just shot herself. There's blood everywhere." Just after 11:20 pm on September 2, 2010, Michelle's boyfriend, St. Johns Sheriff's Deputy Jeremy Banks, called police. He told dispatchers she was unconscious and bleeding. So what did happen to Michelle that night? Surprisingly, there is very little agreement -- even among the experts. The St. Johns County medical examiner initially ruled her death a suicide, but later changed his mind. "I became convinced it was probably a homicide." Dr. Frederick Hobin would not let us videotape our interview with him, but he did allow us to record it. Today, he admits, he doesn't know what happened. "The best I can do now is to say I don't know." Dr. Jerry Findley, a crime scene analyst hired by the Florida Department of Law Enforcement to review the case, concluded that many elements of Michelle's death were "suspicious." He also determined it was extremely unlikely that right-handed Michelle would use her weaker, left hand to hold the gun -- as she would have had to in order for the bullet casings to land where they did. Findley wouldn't talk on camera, saying the case had become too political. But in his report, he questioned why the weapon had no trace of blood on it, even though blood was spattered on Michelle's hands, arms and legs. Findley also found it suspicious that the gun -- which was Deputy Banks' duty weapon -- didn't have any of Deputy Banks' DNA or fingerprints on it, even though he'd worn it to work that day. Findley concluded the evidence in the case, though not consistent with a suicide, was consistent with a homicide. The State Attorney's Office believes Michelle killed herself, and two other Medical Examiners who reviewed the case agree. But the Florida Department of Law Enforcement believes the case was a homicide. And in March, after Special Prosecutor Brad King announced he would not pursue the case, the agency sent a letter asking him to reconsider, saying "this case clearly warrants an inquest into the death of Michelle O'Connell." Michelle's sister Jennifer Crites also wants more investigation. "I believe we deserve a grand jury" Jeremy Banks' attorney Mac McLeod disagrees. "There's nothing in this young man's past to suggest he's even capable of this type of conduct. He's not abused anybody, and he sure as hell didn't kill anybody. He was as distraught as anybody about this death." Jeremy Banks didn't want to talk to us for this story, but he admitted to police that he and Michelle had a tumultuous relationship. During the year they dated, they fought often, and she frequently threatened to leave. On at least a couple of occasions, he told police, that anger turned physical. In a recorded interview, he told investigators of one occasion. "She threw her chair down she said, 'I hate you Jeremy Banks!' and she ran at me. That was when I grabbed her arm put her on the ground and held her there." Michelle's mother, Patty O'Connell, long suspected abuse in their relationship. "I went to counseling through the Sheriff's Office. I said: my daughter is being abused. My granddaughter's being abused. 'Well, we can't do nothing about Michelle but we'll take care of Alexis.' And I said OK. "And then a couple days later Michelle's dead. She's gone." But Banks has insisted all along that Michelle's death was a suicide, and his story has never wavered. "One thing that liars don't do is they're not consistent," says attorney Mac McLeod. "And Jeremy, knowing what occurred, has always been consistent." Jeremy's attorney observes that two other medical examiners determined Michelle's death was a suicide. He points to several desperate sounding texts Michelle sent that night. He also notes that paramedics found her jean pockets stuffed with painkillers belonging to Deputy Banks, though no drugs were found in her system. But what may be the most unsettling piece of evidence didn't emerge until months after Michelle's death. Two female witnesses, who lived a few hundred yards from the house where Michelle died, maintain they hear a woman screaming for help. The women declined First Coast News' interview requests, but both signed sworn statements and passed polygraph tests. St. Johns County Sheriff's Office spokesperson Chuck Mulligan says the agency has been torn apart by the case -- and not just because Jeremy Banks is a deputy. At the time of Michelle's death, both her brother and her mother worked for the Sheriff's Office. "There's been a lot of rumors, there's new information that arrives months after the case," he says. "It's been very trying on all the individuals." Eventually, Michelle's mother Patty O'Connell says that working in the office became too stressful. "I cried and cried because I wanted to tell so many people in that office my daughter did not kill herself. But for almost two years I had to be quiet. I couldn't say anything about my daughter. I had to work there and act like nothing ever happened." Patty O'Connell ultimately quit. Her son, Deputy Scott O'Connell, was fired in part because of his angry reaction to the prosecutor's decision not to prosecute. The family is still angry. With so many interconnections between Michelle and the Sheriff's Office, her family says, the department should have turned the investigation over to FDLE right away. Instead, the Sheriff's Office waited four months before asking the state to step in. "There are very complicated issues in the case," says Sgt. Mulligan. "In my 25 years in the Sheriff's Office, I've never seen a case with as many people involved and as many experts involved -- and still have questions in the end." But despite the family's pleas and the lingering questions, after almost two years on administrative leave, Deputy Jeremy Banks returned to work six weeks ago. Whether he'll be able to do his job effectively remains to be seen. Says his attorney, "The biggest problem Jeremy has is this. It's this."

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