Brian Diez pulled up to his sister’s house in Rancho Cucamonga early Sunday morning.

His brother-in-law answered the door. It was almost 3:30 a.m.

Diez left his 13-month-old son and 4-year-old daughter with him, walked to his truck and then shot himself in the head.

San Bernardino County Sheriff’s Department officials released few other details regarding the moments surrounding when Diez committed suicide.

The 26-year-old Lake Havasu City resident made the estimated 250-mile trek to California in three and a half hours — right after he shot and killed five people — including his children’s mother — in a quiet neighborhood here late Saturday night.

Gloria Gomez, a SBCD deputy assigned to the Rancho Cucamonga Police Department, said Diez never entered the home, and reports did not “indicate that he said anything,” other than asking for his sister.

The shooting occurred in the 11900 block of Rue Way.

Jodi Miller, a spokeswoman with the Sheriff’s Department, would not release the names of Diez’s sister and brother-in-law. She would also not confirm if Diez used the same weapon — a .40 caliber semi-automatic handgun — in the city’s worst homicide to take his own life.

Miller said deputies contacted California Children and Family Services. Today’s News-Herald was unable to speak with a representative of the organization Wednesday.

The Inland Valley Daily Bulletin reported Aug. 30 that Diez had lived in Glendora, Calif., outside of Los Angeles at least in 2005. The newspaper covers eastern Los Angeles County and western San Bernardino County.

The Daily Bulletin also reported that neighbors of where his father reportedly lived in Glendora said they remembered Diez never causing trouble.

In an Aug. 29 Daily Bulletin article, a man at the Rue Way home said it was too soon to talk.

Diez entered 23-year-old Deborah Langstaff’s home in the 300 block of Opossum Drive in Lake Havasu City and opened fire around 11:50 p.m. Aug. 28.

Langstaff, who was killed, was the mother of the children and had been estranged from a long-term relationship with Diez.

Also killed were Primo Verdone, 24; Russell Nyland, 42; Ashleigh Nyland, 20; and Broc Kelson, 20. Debbi Nyland, 44, survived the shooting and was taken to a Las Vegas hospital and is in good condition, according to a hospital spokesperson.

Police have said the gathering could have been to celebrate Verdone’s birthday.

You may contact the reporter at jleatherman@havasunews.com