Kate Kasten, a 39-year-old mother of two, had moved to St. Charles, Mo., about a year ago, a few months after losing her husband to a long battle with cancer.

The move had represented a new start for the family, which included daughter Zoe, 8; son Jon, 10, and her divorced mother, Jane Moeckel, 61, the St. Louis Post-Dispatch reported.

But on Friday that new start came to a shocking, tragic and violent end when Kasten’s boyfriend, identified as Richard Darren Emery, 46, killed the family members inside their home, authorities said.

Emery later exchanged gunfire with police, and stabbed a woman multiple times while trying to steal her car, authorities added. He was eventually found bleeding from gunshot wounds inside the restroom of a convenience store after leading police on a seven-hour manhunt, according to reports.

On Monday, Emery appeared in court, FOX 2 of St. Louis reported. He is due to return before the judge Jan. 8.

Suspect Richard Emery and victim Kate Kasten are seen in a photo posted online. (Facebook)

He could get the death penalty if convicted in the case. He faces 15 felony counts, including for murder, armed criminal action and assault, FOX 2 reported.

Moeckel had called 911 during the attack, and police could hear the sound of gunfire in the background, St. Charles police Lt. Tom Wilkison said.

“It was a gruesome, gruesome scene,” St. Charles County Prosecutor Tim Lohmar said at a news conference Saturday, describing the discovery of the bodies by police.

On Sunday night, St. Charles residents gathered for a vigil in memory of the victims.

“This family did not deserve this,” one vigil attendee told FOX 2. “They will be missed by so many people. My heart is broken, and I loved them all so much.”

Moeckel’s ex-husband told the Post-Dispatch that he had recently had dinner with the family, and saw no signs of possible trouble to come.

“There was never an indication that something like this could happen,” Moeckel said. “The kids loved him. The big question is what the heck happened?”

The Associated Press contributed to this story.