Minneapolis police say two children were shot to death in a snowy front yard Sunday morning on the 2700 block of Oakland Avenue South. Hours later, a woman and man were also found dead inside the home by SWAT team members.

The residents of nearby homes were evacuated, some taking refuge on a Metro Transit bus as snow fell and temperatures dipped below freezing.

Police negotiators tried unsuccessfully to reach out to the suspect all morning and early afternoon, until SWAT team members entered the residence and discovered the additional bodies.

MPR News confirmed that the four people who died were a woman, her ex-husband and their two sons. On Tuesday, the Hennepin County medical examiner’s office identified them as Kjersten Marie Schladetzky, 39, Nelson Sidney Schladetzky, 8, William David Schladetzky, 11, and David Stout Schladetzky, 53. Kjersten Schladetzky was also stabbed in the chest.

David Stout Schladetzky killed himself with a gunshot to the head, the medical examiner’s office said.

Minneapolis police received the call of the shooting at 10:03 a.m., according to spokesperson John Elder. Officers responding to the call saw the two boys with apparent gunshot wounds in the front yard. Then they heard gunfire inside the home, Elder said.

The officers moved the children to a squad car to get them away from the house. Elder said both preteen children were declared dead.

“All indication is that the children were outside playing in the snow when the suspect pulled up and shot them both,” Elder said.

Law enforcement authorities work at the scene of a shooting in south Minneapolis on Sunday. Jon Collins | MPR News

Because police didn’t know whether other people were in the home, they treated it as a possible hostage situation.

Police used the parking lot of the nearby American Swedish Institute to mount their response. SWAT team members, high-ranking police officials and negotiators were on the scene. Elder said every officer in the Third Precinct was working on the investigation, and that officers from other parts of the city picked up other emergency calls in the precinct.

"There's not a race to finish this," Elder said referring to the apparent standoff at around 2 p.m. "Right now the concern is for anyone who's in that house, and we will continue to move methodically through this."

Elder said a bomb squad was brought in so that authorities could use the squad’s robotic camera to give police a better view without putting officers in danger. He said they retrieved some video from the robots.

Two blocks of Oakland Avenue were closed off, and at least eight nearby homes were evacuated as a precaution.

Karin Maris, who lives down the block, said she heard something like gunshots in the morning. As Maris walked her dog, she saw police and SWAT members all over the street.

Police suspect the case to be a “domestic” homicide. Authorities also believe a woman fatally shot Thanksgiving night to be a domestic homicide victim.

Referring to the officers who brought the children out of the area, Elder said “this is something that will live with them forever.” Police chaplains were on hand to support officers and other staff.

Chief Medaria Arradondo said on Sunday afternoon that it was a sad day for the city of Minneapolis.

“This is certainly not the conclusion that I as chief would have wanted, but I know that our men and women who responded here today did all they could to preserve and save lives,” Arradondo said.

Police said there’s no further danger to the public and they are continuing to investigate.