SACRAMENTO -- This week marks the 35th anniversary of a cold case that still has Sacramento Police stumped. 

On July 15th, 1978, a 27-year old named Norma Houghland and her two sons, 9-year old Richard and 6-year old Tommy went missing.

"It was a hot summer, Norma didn't have air conditioning... It wasn't unusual for her to drive her kids in the car to cool off," Sacramento Police Officer Michele Gigante said.

After a week of not hearing from them, her family checked their apartment, Gigante said. Norma and the boys belongings, including clothes and other personal items, were all there, but there's been no sign of the three -- or any leads, in the last 35 years.    

If you know anything about the three, or their disappearance, you're asked to call the Sacramento Police Department's Missing Persons Unit at (916) 808-0650.

Norma Houghland, was 27 when she went missing.

Ricky was 9 when he went missing.

Tommy was 6 when he went missing.