A Calvert County grand jury indicted 18-year-old Gabriella Syniya Hill on four felony counts, including attempted first-degree murder, stemming from a stabbing at a private pool party in Prince Frederick over the summer. But Hill's criminal case has stalled entirely, after state mental health evaluators twice found her incompetent to stand trial in the months since her arrest.
The grand jury handed up its indictment on October 19, charging Hill with attempted first-degree murder, attempted second-degree murder, first-degree assault, and second-degree assault, according to SoMdNews. The charges trace back to July 27, when 48-year-old Michael Charles Heinhorst was stabbed in the neck during a gathering at a swimming pool at a private residence off Sixes Road in Prince Frederick — a property identified in charging documents as Hill's own residence.
According to the statement of charges filed by Trooper C. Williams of the Prince Frederick state police barracks, Heinhorst was in the pool with his daughter when Hill told him to get out. Heinhorst reportedly replied, “No, we're having fun.” Court records allege Hill stabbed him in the neck after he climbed out of the pool; Heinhorst pushed off his attacker and fell back into the water before receiving emergency transport to the University of Maryland Capital Medical Center, court documents cited by SoMdNews state. A fixed-blade kitchen knife was recovered near the pool and is believed to be the weapon used in the assault. Hill was arrested at the scene.
A Pattern of Violence in a Single Month
Court records show the pool stabbing was not an isolated incident but the third violent allegation against Hill within the span of about three weeks in July. Separate altercations on July 3 and July 19 had already generated four counts of second-degree assault against her, per the same court records. The July 19 case, according to a report from Southern Maryland News Net, involved an alleged attack on a hospital nurse just eight days before the stabbing at the pool.
At the time troopers took her into custody for the stabbing, state police initially charged Hill with carrying a dangerous weapon with intent to injure, in addition to attempted murder and assault, the outlet's report notes. Court documents reported by SoMdNews on October 20 reveal Hill now also faces a separate second-degree assault charge stemming from an incident inside the Calvert County Detention Center, where she has been held without bond since her July arrest.
Trial on Hold Over Competency Findings
Despite the severity of the indictment, Hill's case cannot move forward in its current form. The Maryland Department of Health found her incompetent to stand trial twice this year — once around August 5 and again on September 14, according to court documents cited by SoMdNews. Section 3-104 of the Maryland Criminal Procedure Code addresses competency. No arraignment or trial date has yet been set.
The stakes for Hill remain steep whenever proceedings do resume. Under Maryland Criminal Law Code Sections 2-205 and 2-206, a conviction for attempted first-degree murder carries a maximum sentence of life imprisonment, while attempted second-degree murder carries up to 30 years, according to FrizWoods. Attempted first-degree murder requires prosecutors to prove premeditation and specific intent to kill.
A Rare Case of Violence in Calvert County
Hill, a member of the Calvert High School Class of 2026, faced charges in the pool-stabbing case. The case stands out against Calvert County's broader public safety record: the Calvert County State's Attorney's Office reported in January 2025 that the county logged 1,634 incidents per 100,000 residents in 2024, giving it the lowest overall crime rate in Maryland against a statewide average of 3,771 per 100,000.
For now, the four felony counts against Hill remain in legal limbo, suspended by the competency rulings rather than resolved by them. Whether or when she will be found fit to face a jury is a question that rests with state mental health evaluators, not the courts.
