DENVER - Denver Detectives finished searching a house at East 49th Avenue and Pearl Street  in the Globeville neighborhood where a mother and her two young children were shot and killed Wednesday morning.

They called it "a horrific scene."

A fourth victim, a critically injured toddler, was carried out of the home on a stretcher and loaded into a waiting ambulance. The child underwent surgery at Denver Health Medical Center Wednesday morning.

"At this time we're not looking for any suspects," said Denver Police Cmdr. Ron Saunier. 

7NEWS asked asked Saunier is the shooting was the result of a murder-suicide.

"We're still early on (in the investigation)," he said " There are still a couple of things that we need answers to."

A family member identified the dead as 23-year-old Mayra Perez and two of her children, a 6-year-old daughter, Nivek (pronounced: "Nah-Vay"), and a 2-year-old son, Eric.

The woman's 3-year-old daughter, Isabel, was rushed to Denver Health Medical Center. 

Family members told 7NEWS that she had been shot in the head.

"The patient remains in critical condition and is surrounded by family," said an 8 p.m. update  from the hospital.

Ricky Perez, the father of Eric and Isabel, was not injured. It's unclear where he was at the time of the shooting.

A family member, who did not wish to be identified, said that all early signs are pointing to Mayra Perez shooting her children and then turning the gun on herself. 

"I know they had an argument the night before," said the family member. "He didn't stay the night at the house."

The family member said they had the gun for protection.

"We are just in shock," said the family member. "We cannot believe this has happened to our family."

Denver Police Chief Robert White said officers were called to the home at 6:55 a.m. When officers walked inside,  they found the bodies of the woman and two children and the injured child.

Police spokesman Lt. Matt Murray said it appeared that all four had been shot.

"I would ask that we all keep those involved, those family members that are going to be faced with this horrible tragedy in our thoughts," White said.

Saunier said, "Any time you have kids involved, it's a horrific event ... My heart goes out to the family and friends of those involved."

Stunned neighbors said they'd often see the children riding their bikes and tricycles.

"If there's neighbors or somebody that has information, I'd ask them to come forward,"  saId Saunier, at a 3 p.m. news conference.

AIRTRACKER7 flew over the area around 7 a.m. and spotted heavy police presence centered on a small, flat-roofed duplex. A tricycle and a small toddler-sized basketball hoop could  be seen in the back yard.

Neighbor Debbie Martinez  told 7NEWS she didn't hear any gunshots early Wednesday and didn't know anything was wrong until she saw police and news crews outside the home. Martinez said she still felt safe in the neighborhood, but was shocked and saddened that the victims included children.

Martinez said a Hispanic family had moved into the house about six months ago.  A family member said the family had moved from Las Cruces, N.M.

Martinez said she saw the mother putting the children into the car a few days ago and everything seemed OK. The neighbor said she'd never heard arguing coming from the home.

Another neighbor said they heard an argument at the home last night, but police couldn't confirm that.

A candlelight vigil was held for the family Wednesday night in the Globeville neighborhood.