A Sunday school teacher shot and killed his 7-year-old son before turning the gun on himself, authorities in Longview, Washington announced on Friday.

The cause of death in both cases was a gunshot wound to the head based on autopsy results, according to Fox 12 Oregon.

Found dead inside their home were 34-year-old David Michael Pittore-Montiel and his son, Michael Landon.

"From evidence obtained from the scene and from the post-mortem examinations it is believed that David Michael Pittore-Montiel shot Michael Landon Pittore-Montiel with a handgun then using the same handgun shot himself," according to a statement issued by the Cowlitz County Coroner's Office on Friday.

David Michael, a Criminal Justice graduate, was ealier reported to have tried to reach out to people on social media early Thursday morning, indicating he was in a crisis, KOIN6 reported. People who responded to Pittore-Montiel said they gave him encouraging words, and then alerted police about his suicidal behavior.

Longview police, responding to calls they received at around 5:30 a.m. Thursday morning, quickly went to Pittore-Montiel's apartment in the 900th block of 8th Avenue. They heard gunshots before they could enter his apartment. They then found both the father and the son dead.

Pittore-Montiel's neighbours told police officers that he was a single father. His ex-wife Crystal Montiel, who mourned for their loss on Facebook, lives in Vancouver, Washington, The Christian Post reported.

According to his LinkedIn profile, Pittore-Montiel worked as an Office Administrator at the Lower Columbia Community Action Program (LCCAP), an organisation formed as a vehicle for former President Lyndon B. Johnson's "war on poverty." LCCAP's Kathy Bates, however, said he hadn't been in the company for a long time and had been working as a manager at McDonald's.

A local Mormon Church said Pittore-Montiel was a Sunday school teacher. Longview Public School Superintendent Dan Zorn said his son Michael was a first-grader at Northlake Elementary School.

In a Facebook post, LCCAP highlighted Pittore-Montiel's struggles in life and how he overcame them. It said he grew up in foster care, suffered from homelessness after being discharged from the military, and even had his identity stolen. Yet, he was able to overcome all of those trials.

LCCAP said with some help, Pittore-Montiel found housing for himself and his son, and received counsel to help deal with his past traumas. He eventually landed a job, rebuilt his credit, rose up the ranks to become a restaurant manager, and even went back to school to earn a Bachelor's degree.

LCCAP further emphasised the strong father-and-son connection between the two victims. It said in the same Facebook post that both of them were frequently seen riding their bikes together around town. Additionally, Pittore-Montiel is remembered as often expressing that Michael "meant everything to him."