A 21-year-old Paxton man pleaded not guilty to two counts of second-degree murder Wednesday, Oct. 14, in the deaths of an Andover father and his 8-year-old daughter.

Matthew Sweeney was arraigned in Middlesex Superior Court in Woburn on the murder charges and additional counts of motor vehicle homicide, operating under the influence and operating to endanger, the Eagle-Tribune reported. The charges stem from a fiery crash on Route 28 in North Reading on Aug. 22 that killed Samir Naili, 35, and his daughter, Kashmira Naili, 8, both of Andover.

The murder indictment replaced the original vehicular homicide and OUI charges filed after Sweeney's initial court appearance in August.

What prosecutors allege

Around 10:45 p.m. on Aug. 22, Sweeney was driving an Acura MDX at speeds near 100 mph on Route 28 when he struck a car stopped at a red light, according to Middlesex County District Attorney Marian Ryan. The collision caused the car to become engulfed in flames. Despite efforts by first responders and bystanders, Samir and Kashmira Naili died at the scene.

Before the fatal crash, Sweeney was allegedly involved in a hit-and-run in Methuen, WCVB reported. An Andover police officer spotted his vehicle and began a pursuit. Authorities said Sweeney fled at speeds of 100 mph.

Officers searching Sweeney's vehicle after the crash found two open alcoholic beverage containers and a cup smelling of alcohol, according to police reports cited in Hoodline's account. Sweeney allegedly displayed slurred speech and bloodshot eyes and refused field sobriety tests.

The victims

Liz Powell-Naili, the victims' mother and grandmother, identified the victims after the August crash. In an interview with WCVB at the time, she described her son as a wonderful father who loved music and loved to teach his daughter. Kashmira had been about to start third grade in Andover Public Schools.

"I don't think he should get away with it because it's a mental illness," Powell-Naili told WCVB in August.

Defense raises mental health history

Sweeney's defense attorney, Kevin Mahoney, has argued his client's mental state will be central to the case. During an August court appearance, Mahoney said Sweeney suffered from a history of lost time and blackouts and had no recollection of the crash, according to Hoodline, citing CBS News.

Mahoney disclosed in court that Sweeney was hospitalized for bipolar disorder in 2024 and again in December 2025, when he stopped taking prescribed medication due to side effects, Hoodline reported.

After his initial arraignment in August, a judge set bail at $250,000 and ordered Sweeney committed to Bridgewater State Hospital for a psychiatric evaluation.

Why murder, not just homicide

Under Massachusetts law, a second-degree murder conviction requires prosecutors to prove malice aforethought. That means the defendant intentionally committed an act a reasonable person would know creates a plain and strong likelihood of death. A conviction carries a sentence of life in prison, with parole eligibility after 15 to 25 years.

The case now moves forward in Middlesex Superior Court. No future court date has been announced.