A fifth victim is still fighting for his life.
An 18-month-old girl and a three-year-old boy are among the victims.
The incident happened around 6:45 Sunday morning at the Silver Lake Apartments on Belmont, near Minnewawa in East Central Fresno.
Witnesses say the children's mother is responsible for the early morning violence, before taking her own life.
Jesus Gonzalez heard what sounded like gunshots just before 7 a.m. Sunday morning.
Moments later, his neighbor, who lives just a few feet away, knocked on his door, asking for help.
Jesus Gonzalez said, "And I opened the door, and he fall in front of me, and I take him and I put him inside my home."
Gonzalez says his neighbor had been shot and stabbed multiple times.
Before he was able to shut the door, he claims the man's wife tried dragging him back outside.
That's when Gonzalez says he yelled at her, and scared her away. "Hey! What happened? What happened? And she went into her house," Gonzalez said.
Gonzalez says his neighbor told him that his wife was the one responsible for all of the blood shed inside their shared apartment.
According to Fresno Police, four bodies were inside the home.
Among the dead are two toddlers, an 18-month old girl, and a three-year-old boy.
Also dead: a man and a woman in her twenties, who police say, pulled the trigger on herself.
Capt. Dennis Bridges said, "This was a terrible tragedy, no matter what the sequence of events, and exactly what happened here. the two small children were deceased the adult male was deceased and the apparent mother of the children who appears at this time died of a self-inflicted gunshot wound but all around this is a terrible tragedy."
All day Sunday, neighbors watched in shock as investigators collected evidence.
Some who knew the family say they ever expected anything like this.
Mariah Gonzalez said, "Kept to themselves, they were respectful. It didn't seem like something like this would happen to them. This tragic."
The husband was listed in critical condition Sunday night.
As for the man's body found in the apartment, neighbors say he is a cousin of the woman.
The victims' names have not been released.
Stay tuned to Action News and ABC30.com for the latest on this story.
