Now the reward for information leading to an arrest has grown to $450,000.
The Costa Mesa city council has added $50,000 to the reward total.
Aiden Leos was fatally shot on May 21 while his mother was driving him to school.
CHP said the suspect vehicle continued driving northbound on the 55 Freeway to the eastbound 91 Freeway toward Riverside. The suspects were described as a female driver and a male passenger who pulled the trigger.
Last week investigators released a photo of the suspects' car - described as a 2018 or 2019 white Volkswagen Golf SportWagen with non-tinted windows.
Aiden Leos shooting: CHP releases image of car involved in killing of 6-year-old boy on OC freeway
A website is up in hopes of catching a shooter as the young boy's family prepares to say goodbye.
Sister of child shot in Southern California describes little brother's final moments
Anyone with information can contact the CHP Santa Ana Area Office at (714) 567-6000 or email firstname.lastname@example.org.