(LOS ANGELES) — A man who was arrested after plowing his car into dozens of police recruits who were out for a run in Los Angeles County early Wednesday has now been released as an investigation into the incident continues, officials said.

The driver, 22-year-old Nicholas Gutierrez, was arrested for suspicion of attempted murder on a peace officer, the sheriff’s department said on Thursday. He was later released from the LA County jail “due to the extreme complexity of the investigation, which includes ongoing interviews, video surveillance review, and additional evidence needed to be analyzed,” the LA County Sheriff’s Department said Friday.

About 75 recruits were on the run with 25 of them suffering injuries in the crash. The group was mostly Los Angeles Sheriff’s Department recruits, but also included others from nearby police departments, including Pasadena and Glendale.

“It looked like an airplane wreck, there were so many bodies scattered everywhere,” LA County Sheriff Alex Villanueva said at a news conference Wednesday.

Five of the recruits were critically hurt, four suffered moderate injuries and 16 have minor injuries, officials said at a news conference.

Injuries included head trauma, loss of limb and broken bones, officials said. At least one victim was on a ventilator, the sheriff said.

Gutierrez suffered minor injuries, LA County Fire Capt. Sheila Kelliher said Wednesday.

The cause of the crash is unknown. The California Highway Patrol said it’ll investigate whether the crash was intentional or the result of distracted driving or driving under the influence.

The charge of attempted murder on a peace officer was based on statements made by recruits and other witnesses, including that the car seemed to be accelerating as it went into the group, sources leading the investigation told ABC News. Interviews are ongoing, the sources said.

Villanueva said Gutierrez blew a 0.0 on a Breathalyzer test.

“It looks like it’s an accident, a horrific accident,” Villanueva said.

The recruits were running on a routine route in Whittier at the time of the crash, which took place around 6:29 a.m. Wednesday, while it was still dark out, officials said.

“Road guards” wearing reflective vests ran on the outside of the recruits, officials said.

The sheriff’s office also had two patrol cars escorting the runners.

The accident took place just outside of a fire station, so firefighters immediately raced to the scene, officials said.

Some recruits estimated the car was going about 30 mph, officials said.

“It is hard to see, because these young people are getting ready to go put themselves in the line of danger in their career. And who knows that while you’re training to do that you are actually in harm’s way,” Kelliher said at a news conference. “So my heart goes out to all of them as they pursue this career. I hope that they all have speedy recoveries.”

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