Milpitas police on Thursday said the case of four family members found dead inside an apartment earlier this week is being investigated as a murder-suicide. The bodies of 36-year-old Vinh Nguyen, 36-year-old Betty Pham, their 9-year-old son and 4-year-old daughter were found Tuesday night when officers were called to the Turing Apartments to conduct a welfare check, police said. Each family member had sustained a single gunshot wound. Nguyen, the father, is suspected of pulling the trigger. “This tragedy is a very difficult reminder of the importance of addressing domestic violence and gun violence,” Milpitas police Lt. Tyler Jamison said. “The loss of their lives was preventable.” Authorities believe the shooting happened sometime last weekend, most likely Saturday evening, Jamison said. A motive wasn’t immediately known. “Our detectives are still going through digital evidence and all the evidence that they have to determine if there’s any notes, any additional evidence that was left from the suspect or any additional information,” Jamison said. Officers were initially dispatched just before 9 p.m. Tuesday to the apartment complex, located at 1355 McCandless Dr., to perform a welfare check after relatives of the family reported that they hadn’t spoken with their loved ones in several days, police said. “When the family called for the original welfare check, they said that it was just abnormal that they hadn’t spoken with their family members for the past several days,” Jamison said. “Usually they spoke to them every two to three days and hadn’t heard from them. That’s what caused them concern.” No prior police service calls had been made at the family’s apartment, according to Jamison. “This was our first contact as a police department with them,” he said. A handgun legally registered to Nguyen was recovered at the scene, Jamison said. Neighbors said they had seen the family members around the apartment complex frequently and never noticed anything unusual. “Very easygoing couple,” one resident said. “I had numerous conversations with them.” If you or someone you know is in crisis, call or text 988 to reach the Suicide and Crisis Lifeline or chat live at 988lifeline.org. You can also visit SpeakingOfSuicide.com/resources for additional support.