The resident, Ellie Washtock, 38, had requested records in the case and had been in touch with Ms. O’Connell’s family in the months before being fatally shot in January of this year.

Washtock was not the only one who had searched for answers in Ms. O’Connell’s case, which drew the scrutiny of state investigators. A 2013 examination by The New York Times and the PBS program “Frontline” raised questions about forensic evidence and found shortcomings in the St. Johns County Sheriff’s Office’s handling of the case, which involved one of its own deputies, Jeremy Banks. Ms. O’Connell, a single mother, had been in the process of breaking up with Mr. Banks when she was found fatally shot, with his service weapon by her side.

Both the sheriff’s and the medical examiner’s offices for Putnam County declined to release records related to Washtock’s death, citing a continuing investigation.

It is unclear how Washtock, who had at various times identified as male and female, identified at the time of death. Although court records indicate a name change to Ellie in 2009, some who knew Washtock more recently knew Washtock as Eli. The Times is using Washtock’s surname.

Washtock, who had two children and a background in auto mechanics, moved to Florida from Wisconsin several years ago, according to Nick Uttech, a childhood friend.