(CNN) A trucker has been charged with 40 counts, including vehicular homicide and first-degree assault, in the deadly and massive traffic pileup outside Denver last week, the Jefferson County district attorney's office said Friday.

Rogel Lazaro Aguilera-Mederos, 23, faces 36 felonies: four counts of vehicular homicide, six counts of first-degree assault, two counts of vehicular assault and 24 counts of attempt first-degree assault, among others, District Attorney Pete Weir said at a news conference.

The four other charges are one count of reckless driving and three counts of crime of violence. Weir explained that the six first-degree assault charges involve the four killed and two seriously hurt and the 24 counts involved people in all of the vehicles in the collision.

.@LakewoodPDCO Chief Dan McCasky at a press conference regarding charges against Rogel Lazaro Aguilera-Mederos: "Our goal is to seek justice... We won't rest until we have thoroughly investigated this matter." @CBSDenver pic.twitter.com/riaOtKV5ln — Mekialaya White (@Mekialaya) May 3, 2019

"There is a relationship between each count that was filed and a separate individual that either died, was seriously hurt, or was placed in extraordinary risk of seriously bodily injury or death," Weir said. "The number of counts reflects the magnitude of the incident and the number of people that were hurt or could have been hurt by his actions."

At a brief Friday court hearing, Aguilera was seen on a video link, with his attorney was seated next to him.

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