The state has upgraded the charges against a 26-year-old Massachusetts woman accused of causing the April 8 crash on Interstate 395 that resulted in the death of Lisa C. Delprete of North Haven.

Dina Senibaldi of Everett, Mass., has been served with an arrest warrant charging her with second-degree manslaughter with a motor vehicle and second-degree assault with a motor vehicle, according to New London Superior Court prosecutor Christa L. Baker.

Senibaldi was initially charged with driving under the influence of alcohol or drugs, possession of marijuana, possession of narcotics, possession of narcotics not in the original container and driving without a license. Baker said state police obtained an arrest warrant for the additional charges after completing their investigation, which included a reconstruction of the accident.

Senibaldi, who is free on a $75,000 bond, will be arraigned on the new charges Nov. 4. The court papers detailing the new charges have not yet been made public.

According to earlier reports, Senibaldi was driving a Dodge sedan that struck a Jeep from behind about 0.7 miles south of Exit 77 on I-395. The Jeep flipped onto its passenger side and came to rest on a guardrail, trapping Delprete, 45, of North Haven, in the passenger seat. She later died of a head injury.

The driver, 52-year-old Edmund Davis, was hospitalized with serious head and chest injuries.

The police said Senibaldi and a passenger, 25-year-old Marirose Lynch, also of Everett, were sitting on a curb, “hysterical,” as rescue crews and troopers arrived at the scene. Senibaldi had bloodshot eyes and slurred speech. She complained that her head hurt but refused treatment. She failed a field sobriety test at the scene and later refused to submit to urine or blood tests. Police said they found plastic bags containing oxycodone pills and marijuana in her possession. Lynch was treated at Lawrence & Memorial in New London for a cut to her forehead.