Arrest made in deaths of 2 Colorado teens

— -- A 19-year-old man was booked on first-degree murder and kidnapping charges in the deaths of two teens who were found dead on the side of a Colorado road, authorities said.

Gustavo Marquez, 19, was also charged with aggravated robbery and child abuse resulting in the deaths of Derek Benjamin Greer, 15, and Natalie Partida, 16, according to the El Paso County Sheriff's Office.

The victims' bodies were found on the side of a road about 15 miles from their Colorado Springs high school.

"I am so happy there is finally justice for my son and Natalie," said Greer's mother, Heather Ferguson. "The case is still ongoing so it's not over yet."

The deaths were ruled homicides but the cause was not clear.

"They had a whole life to live," Greer's cousin, Hannah Ortega, told ABC News Friday. "They don't get to have kids, they don't get to graduate high school, they don't get to work their dream jobs, they don't get to live anymore. Nobody deserves to get their life taken."

Marquez is scheduled for a court appearance on April 5, according to records.