Updated

A driver had prescription medication in his system when his van crashed into a sedan and killed five members of a California family headed to Disneyland, authorities said.

Investigators believe Joshua Smith, 30, lost consciousness just before leaving his lane and causing the collision on May 11 while the sedan was at a stop sign, the San Bernardino County Sheriff's Department said in a statement Monday.

The van came to rest on top of the family car, authorities said without elaborating.

Investigators believe the crash was caused because Smith was driving under the influence of a narcotic. Authorities did not name the medication.

Prosecutors were considering whether to file charges.

The victims were 25-year-old Angelica Garcia; her boyfriend, 30-year-old Gerardo Jimenez; and their children, 2-year-old Ivan Jimenez and 3-year-old Cindy; and Garcia's 9-year-old son, Freddy Garcia.

Relatives of the victims said the family was making the drive to Disneyland from Hesperia, a desert town east of Los Angeles, to celebrate Cindy Jimenez's upcoming fourth birthday.

Smith suffered minor injuries. A telephone listing for him was disconnected.

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