Arson investigators are analyzing the scene of an early Sunday morning house fire on the 500 block of Lincoln Boulevard that killed Helen and Troy Spaulding, a couple in their 90s who used wheelchairs and had been married 70 years.

The Santa Monica Fire Department confirmed investigators and public safety officials are working to determine what caused the blaze, according to the Santa Monica Mirror. No cause or suspect has been identified publicly.

The fire broke out around 2:50 a.m. Sunday, Aug. 9, at the Spauldings' older English Tudor-style home. When crews arrived, the single-family residence was "fully involved with heavy fire on multiple sides," according to a department statement reported by KTLA. A vehicle parked in the driveway prompted firefighters to push inside while suppressing the blaze.

Division Chief James Altman told the Los Angeles Times that crews found both victims in a first-floor bedroom and removed them "almost simultaneously." Advanced life support was initiated, but neither could be revived.

The couple normally had a caretaker with them, but no one was on duty at the time of the fire, Altman said.

Rick Garcia, the Spauldings' caregiver, arrived at the scene on the morning of Aug. 9. "They were a lovely couple who had a great relationship," Garcia told KTLA. "They had five lovely children all dedicated to their parents…it's very tragic."

The Spauldings raised all five children in the Lincoln Boulevard home.

No firefighter injuries were reported. Following the fire, the department urged residents to check smoke alarms and review home escape plans.

The Lincoln Boulevard blaze was Santa Monica's second fatal residential fire since June. An elderly man died June 5 after a fire broke out in a second-floor apartment in the 2600 block of 5th Street.

The Santa Monica Fire Department has not announced a timeline for releasing findings from the arson investigation or scheduled a public update.