Milpitas police said Thursday that the case of four family members found dead in 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 evening when officers were called to the Turing Apartments to conduct a welfare check, police said. Each family member had suffered 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,” said Lt. Tyler Jamison of the Milpitas Police Department. “The loss of her life was avoidable.”

Authorities believe the shooting occurred sometime last weekend, most likely Saturday evening, Jamison said. A motive was initially unknown.

“Our detectives are still going through digital evidence and any evidence they need to determine if there are any notes, additional evidence left by the suspect or additional information,” Jamison said.

Milpitas police on Thursday provided an update on the investigation into the deaths of four family members found in an apartment earlier this week.

Officers were initially dispatched to the apartment complex on McCandless Dr. just before 9 p.m. Tuesday. 1355 was sent to conduct a welfare check after relatives of the family reported that they had not spoken to their loved ones in several days, police said.

“When the family requested the initial welfare check, she said it was simply abnormal that she had not spoken to her family members in the last few days,” Jamison said. “Usually they spoke to them every two to three days and didn’t hear from them. That’s what worried them.”

According to Jamison, there had been no previous calls to police at the family’s home.

“That was our first contact with them as a police department,” he said.

A handgun legally registered to Nguyen was recovered at the scene, Jamison said.

Neighbors said they often saw the family members around the apartment complex and never noticed anything unusual.

“Very easy-going couple,” said one resident. “I have 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 on 988lifeline.org. You can also visit SpeakingOfSuicide.com/resources for additional support.