CENTENNIAL, Colo. -- The illegal immigrant accused of causing a fatal accident earlier this month that killed three people will argue he was not to blame for the accident.

A lawyer for 23-year-old Guatemalan native Francis Hernandez said one of the drivers killed in the crash -- Patricia Guntharp -- caused the Sept. 4 wreck by crossing a double yellow line and making an illegal left turn.

However, Aurora police told 7NEWS that they've looked into the issue and it is not illegal to cross a double yellow line when turning into a driveway, as Guntharp was doing. She was turning into the Good Times restaurant at the intersection of Havana and Mississippi.

Prosecutors said that Hernandez was speeding when he blew through a red light, striking the pickup that Guntharp was driving, knocking into an ice cream shop.

The accident killed Guntharp, her passenger, Debra Serecky, and 3-year-old Marten Kudlis. The triple fatal crash led to calls for better immigration enforcement because Hernandez had been arrested at least 16 times before but never deported.

On Monday, Arapahoe County authorities filed a motion to add nine more charges against Hernandez.