Arizona Police Officer Who Rammed Car Into Suspect Won't be Charged, DA Says District attorney said there was insufficient evidence of intent.

 -- The officer who rammed a police car into a suspect from behind will not be charged with aggravated assault, according to the local district attorney's office.

The Feb. 19 incident gained national attention when the dash cam footage from police officer Michael Rapiejko's car was released on Tuesday, showing him ramming into Mario Valencia, a suspect who had allegedly committed a string of crimes earlier that day.

"Given all of the circumstances of this case, there is insufficient evidence to prove that Officer Repiejko had the requisite criminal intent for aggravated assault," reads the letter from Pima County attorney Barbara LaWall to the police chief, dated March 31.

The letter details how Rapiejko came to the decision to hit Valencia.

"As Officer Rapiejko arrived in the area, he could see Mr. Valencia was headed toward some businesses," the letter reads. "There were also other officers in the area. Officer Rapiejko was approximately fifty yards away. Officer Rapiejko determined that Mr Valencia would be able to fire the gun quickly at businesses and therefore decided he needed to stop Mr. Valencia from proceeding any further."

Valencia was hospitalized for two days after the incident, according to police. Valencia was charged with aggravated assault with a deadly weapon, two counts of armed robbery and unlawful discharge of a firearm.

In addition to the dash cam footage, Valencia allegedly was caught on a store surveillance camera obtaining a rifle from Walmart.

Valencia reportedly committed several crimes before police caught up with him, including an alleged arson at a church and invasion of a home, before allegedly stealing a rifle and ammunition from a Walmart. Authorities say the theft was caught on the store's surveillance footage, which has now been publicly released.

On the video, a man identified by authorities as the suspect is seen examining a rifle with the help of a Walmart employee. The staffer walks off at some point, as if to go check something, leaving him standing in the aisle with the rifle placed casually on his shoulder, according to the video.

The female employee returns a short while later, and a fellow shopper and a man with a child appear to approach the suspect and start talking to him before he walks off with the gun and a small box that the employee had handed him.

The entire interaction appears to be calm, including the moment when the suspect walks out of the store with the rifle and box in hand.

The employee appears to be following him but from a distance.

ABC News' Emily Shapiro contributed to this report.