Investigators say 24-year-old Steven Perez from Reedley was drunk when he ran a stop sign and hit the car.
Five people were in vehicle that was struck. The only survivor in that car, the driver, is being treated for brain injuries.
Candles now sit in the place where CHP investigators say 16-year-old twins Amy and Linda Guiba died in the crash.
Also killed in the crash was the twins' brother, 19-year-old Anthony Guiba, and his girlfriend.
"You don't know how hard that was to see my boy. I sat there, they couldn't do nothing for him no more," Rosemary Miranda, the mother of the victims, told Action News.
Amy and Linda were 10th graders at Dinuba High School where they were heavily involved in campus activities.
They were both active in the FFA and at their family's church.
The crash happened along a stretch of Mountain View and Bethel in Fresno County.
Highway Patrol investigators say the crash took place when Steven Perez ran a stop sign on Bethel.
Action News has learned the family was driving back to Dinuba after spending the day at Lost Lake Park near Fresno.
24-year-old Gilbert Guiba was driving the family car at the time of the crash.
Late Sunday night, family members told Action News doctors stopped the bleeding in Gilbert Guiba's brain. He may be released from the hospital soon.
Several of the people in the victim's car were not wearing seatbelts.
The CHP says it's not clear how fast Perez was driving, but it's unlikely seatbelts would have made a difference for those who weren't using them. Sunday night Perez was listed in critical condition. He will be booked into jail as soon as he's released from the hospital on suspicion of driving under the influence, according to investigators.
Because of the decision investigators say Perez made, to drink and drive, the family is now torn apart.
Action News has also confirmed that grief councilors will be on campus at Dinuba High School Monday morning.