Massachusetts police issued an Amber Alert on Wednesday for four children believed to be at "high risk" after being taken with their mother from a home where a woman was found fatally stabbed, officials said.

The children — ranging in age from 11 months to 3 years — and their mother, 26-year-old Louna Eveillard, were believed to be with the children's father, Rodlyn Petitbois, 25, Essex District Attorney Jonathan Blodgett said in a press conference Wednesday.

"We believe the children are at high risk," Blodgett said, identifying the kids as Ryan Petitbois, 3; Lyndsey Petitbois, 2; Lauren Petitbois, 22 months; and Roddick Petitbois, 11 months.

Police are "seeking an arrest warrant for murder in the first degree" naming Petitbois in connection with the fatal stabbing Greenland Etienne, 33, in an apartment in Lynn, about 15 miles north of Boston, Blodgett said.

Etienne was pronounced dead at Massachusetts General Hospital a short time after being found.

Lynn, Mass., police were called to the second-floor apartment just after 1 a.m. Wednesday after receiving a report of a stabbing. Blodgett said authorities believe there was a "social" relationship between the woman and Petitbois but that link was still being investigated.

Police believe that Louna Eveillard was taken against her will, and "do not believe she is part of the abduction of the children," said Blodgett. She is believed to have a significant stab wound to her hand and may be wearing a bandage.

Authorities are still investigating the relationship between Petitbois and Eveillard, which they believe might have turned tenuous, and whether they lived together.

Procopio said Wednesday afternoon that Lynn police found a 1992 white Buick Roadmaster that they believed the family was traveling in. The car, which was empty, was being processing to find clues about the family's whereabouts, but Blodgett said it "is no longer a vehicle of interest."

Blodgett said there have been supposed sightings in Revere, Mass., about 6 miles from the crime scene, but those have not been confirmed. Neither Petitbois nor Eveillard have a valid driver's license.

Authorities said Petitbois came to the United States in 1999 through New York, and state and New York City authorities have been put on notice.

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The Associated Press contributed to this report.