Mystic — Stonington police charged a Groton woman Wednesday with two counts of negligent homicide with a motor vehicle in connection with the death of an elderly local couple on Route 27 in March.

Police had obtained a warrant for the arrest of Carol M. Belli, 73, of 43 Middlesex St., and she turned herself in late Wednesday afternoon. She later was released on a $25,000 bond and is scheduled to appear Oct. 18 in New London Superior Court. If convicted, she faces a maximum penalty of six months in prison and a $1,000 fine on each count.

Belli previously had been charged with driving under the influence of alcohol or drugs after she struck Joanna Wakeman, 78, and her husband, Seth, 88, of Montauk Avenue with her Ford Fusion as they crossed Route 27 near Rossie Pentway. She has pleaded not guilty to the DUI charge and that case is pending in court.

A Stonington police report released in May indicates Belli was arrested at the accident scene after she admitted drinking two vodka gimlets prior to the crash and failed the first part of a field sobriety test.

Her blood alcohol concentration, taken by Breathalyzer one hour and 19 minutes after the 8:07 p.m. incident, was 0.0686 percent, which is below the 0.08 percent legal limit for driving.

Belli had told police the traffic light was green and she was driving at a reasonable speed when, “out of nowhere,” two pedestrians wearing dark clothing walked out in front of her vehicle and she struck them. A witness who was crossing at the same time said the Wakemans, who had just come from dinner at the Latitude 41 restaurant, crossed the street just before getting to the crosswalk and were struck by a car going “a little too fast.”

The police report indicates that Belli, a retired elementary school teacher and principal, was arrested at the scene after submitting to — and failing, police said — just one of three standardized field sobriety tests. Both Officer Daniel Sousa and Lt. Michael Peckham said they observed a “lack of a smooth pursuit” and a jerky eye movement known as “nystagmus” when Belli was asked to follow a stimulus with her eyes, according to the report.

Belli refused the next two field sobriety tests, known as the walk and turn and the one-legged stand, saying she thought it in her best interest to consult with a lawyer and that she was scared. At police headquarters she left a message for an attorney and submitted to a breath test after being read the Implied Consent advisory form, which indicates that under state law, a person who drives a vehicle has consented to testing to determine her blood alcohol content, the report says.

More investigative details, such as the results of Belli’s blood test, are expected to be contained in her arrest warrant, which is expected to become available on Thursday.

j.wojtas@theday.com