RITZVILLE — A Chicago man will spend 30 years in prison for murdering his girlfriend near here on I-90 in front of their young son while high on drugs early in 2015.

Manuel Argomaniz-Camargo, 34, of Chicago, reached a plea bargain with prosecutors from the state Attorney General’s Office, who were handling the case at the request of the Adams County Prosecutor’s Office.

Argomaniz-Camargo pleaded guilty to first-degree murder, with a deadly weapon enhancement, and possession of methamphetamine. He confessed to murdering his girlfriend, Ana Veronica Montelongo Garcia, 24, of Chicago, alongside Interstate 90 near Ritzville.

A few days before Garcia’s death, she, the couple and their 3-year-old son left the Chicago area and embarked on a cross-country trip to Washington. Argomaniz-Camargo confided to investigators that during the trip he continuously snorted meth and cocaine to help him stay awake and drive straight from Chicago to Washington.

As the couple was nearing Ritzville on I-90 in the early morning hours of March 1, 2015 Argomaniz-Camargo stopped the car, opened the passenger side door and pushed Garcia out. Garcia got back into the car and Argomaniz-Camargo grabbed her by the hair and yelled at her about wanting to kill them, “as she was doing witchcraft to the vehicle.”

Argomaniz-Camargo admitted to hitting his girlfriend in the cheek bone with a hammer as she was attempting to get to their son. He described placing a belt around her neck and dragging her out the boy’s point of view.

A passerby contacted authorities after seeing Argomaniz-Camargo walking east on the north shoulder of westbound I-90 holding his son. Authorities responded to the scene and Argomaniz-Camargo was ordered to raised his hands and when he complied, the boy ran into the arms of a Washington State Patrol trooper.

The trooper’s suspicions were raised when Argomaniz-Camargo took off his jacket to reveal he wasn’t wearing a shirt, despite temperatures hovering in the mid-30s, and his hands were covered in blood. The area was searched, and a blood trail was discovered led to Argomaniz-Camargo’s vehicle. Garcia’s body nearby.