CORPUS CHRISTI, Texas >> Police were trying to determine a motive Saturday after they said a man fatally shot four family members at two locations a day earlier, including his father and stepmother inside a Texas nursing home before killing himself there too.

Richard Starry fatally shot himself inside Retama Manor nursing home after killing 85-year-old Ernest Starry and his wife, Thelma Montalvo, Friday night, said Enrique Paredez, a police lieutenant in the Corpus Christi suburb of Robstown. A gun was recovered at the scene.

Paredez said a family member later called officers to the couple’s home where their 13-year-old adopted son and a 41-year-old son of Montalvo were also found shot to death. The names of the other two sons and Montalvo’s age were not released.

The reason behind the shootings was unclear, Paredez said at a news conference.

“As far as a motive, the investigation is too premature at this time to determine,” Paredez said.

Reuben Garcia, whose father lives in the nursing home, was inside the home at the time of the shooting.

“I thought it was just a ladder that had fallen down, that’s what it sounded like to me. Then I heard somebody say run, run,” Garcia said. “So we ran,” getting his father out of the building.

Robstown Police Chief Erasmo Flores said during the news conference that investigators are working “diligently” on the case and that the results will be presented to the district attorney for review.