In all, six people died. Officers responding to the home said they found four people shot dead and two others wounded. One of the injured died of his wounds early Sunday at a local hospital, police said.
The alleged gunman, identified as 26-year-old Brian Diez, was found dead hours later at a residence in Rancho Cucamonga, Calif. The two children - a 4-year-old and a 13-month-old - were unharmed at the house with relatives, police said.
Police went to the Lake Havasu City home after dispatchers received an emergency call at 11:57 p.m. Saturday from a woman who said an intruder had shot several people.
Police identified the dead as 23-year-old Deborah Langstaff, 24-year-old Primo Verdone, 42-year-old Russell Nyland and 20-year-old Ashley Nyland. Wounded were 20-year-old Brock Kelson and 44-year-old Deborah Nyland.
Kelson and Deborah Nyland were taken to a local hospital, where Kelson died early Sunday, police said.
At about 3:30 a.m., San Bernardino County Sheriff's Department deputies were sent to the Rancho Cucamonga home about a reported suicide. Deputies found Diez dead of a self-inflicted gunshot wound, authorities said.
Diez fathered the two children with Deborah Langstaff during a long-term relationship, but the couple had been estranged, Lake Havasu City police said.