An illegal immigrant has been arrested for allegedly ramming an unmarked sheriff's deputy's vehicle, causing a collision that killed a Valley mom.

An investigation into Tuesday night's accident resulted in Guadalupe Perez-Borjorquez, 26, being charged with aggravated assault and second-degree homicide.

Allegedly, Perez assaulted a sheriff's deputy by repeatedly ramming the deputy's car.

According to the Maricopa County Sheriff's Office, Perez was driving erratically on eastbound Durango Street near 27th Avenue around 6:30 p.m. Tuesday.

An undercover narcotics sheriff's detective spotted Perez driving erratically and throwing beer bottles out of his car.

Detective Rob Kinnett, a 15-year veteran of the force, alerted law enforcement and continued to follow Perez.

Investigators say when Perez saw what he believed to be a police car, he put his 1997 Ford Taurus into reverse and repeatedly rammed Kinnett's car.

Kinnett stopped his vehicle and pulled into a nearby parking lot.

Perez proceeded to move his car behind Kinnett's vehicle and ram it from behind. Then he moved to the side and rammed Kinnett's car causing, it to go into oncoming traffic.

At this point, the car collided with a car driven by Nanuma Lavulavu, 46.

The impact of the crash severed her leg and she died at St. Joseph's Hospital this morning.