Updated

California police officials have released the wrong-way driver accused of plowing his SUV into a group of police recruits and staff earlier this week, citing the "extreme complexity" of the ongoing case.

Nicholas Joseph Gutierrez, 22, was released from police custody late Thursday — just hours after officials announced that he had been charged with attempted murder in connection with Wednesday’s devastating wrong-way wreck.

In a shocking reversal, the Los Angeles County Sheriff’s Department said early Friday morning that the agency had released Gutierrez just before 10 p.m. local time Thursday. 

DRIVER IN WRONG-WAY WHITTIER CRASH CHARGED WITH ATTEMPTED MURDER AFTER SLAMMING INTO SHERIFF'S RECRUITS

"Due to the extreme complexity of the investigation, which includes ongoing interviews, video surveillance review, and additional evidence needed to be analyzed, homicide investigators have released Mr. Gutierrez from the Sheriff’s Department custody," the agency said in a press release announcing the change. 

The charge of attempted murder of a peace officer requires evidence that the crime was intentional rather than that someone was mistaken or distracted or otherwise did not mean to commit the act. 

According to local affiliate FOX 11 Los Angeles, Sheriff Alex Villanueva had previously said that investigators had gleaned enough to suspect intent. 

VIDEO SHOWS MOMENTS BEFORE CALIFORNIA POLICE RECRUITS HIT BY CAR

"They did a thorough investigation. They interviewed dozens and dozens of witnesses and victims," Villanueva said, according to the report. "That was the conclusion." 

It was not immediately clear what specifically led to Gutierrez’s release. 

On Wednesday, Villanueva said that 75 recruits from Sheriff's Academy Class 464 had been running near the intersection of Mills Avenue and Telegraph Road in Whittier, just before 6:30 a.m., when they were struck. The group was running with a pair of police vehicles, and some runners were wearing reflective vests.

Nicholas Gutierrez looking at camera

Nicholas Gutierrez is shown at the scene of the wrong-way crash in Whittier, California, on Wednesday. (FOX 11 Los Angeles)

The SUV then plowed into a light pole before coming to a stop.

MORE THAN 20 POLICE RECRUITS INJURED AFTER DRIVER PLOWS INTO GROUP 

"It happened so quickly that just the people that just saw it veer into them, they jumped out of the way, but the people behind had no chance, because they never saw it," Villanueva said. "They didn’t have that sufficient warning."

Nicholas Gutierrez talking to sheriff

Nicholas Gutierrez is shown taking a field sobriety test following a wrong-way crash in Whittier, California, on Wednesday. (FOX 11 Los Angeles)

"There were so many bodies scattered everywhere in different states of injuries," he said.

Gutierrez allegedly had a blood-alcohol content of zero, and a field sobriety test was negative for obvious impairment. Information regarding any drugs in his system was not immediately available.

Nicholas Gutierrez performing test

Nicholas Gutierrez is shown taking a field sobriety test following a wrong-way crash in Whittier, California, on Wednesday. (FOX 11 Los Angeles)

Several recruits suffered injuries that varied from broken bones to head trauma and "loss of limb." As of Wednesday, five were critically injured.

The LASD did not immediately respond to Fox News Digital’s request for information related to the victims’ conditions.

Los Angeles County sheriff's recruits struck

Two investigators stand next to a mangled SUV that struck Los Angeles County sheriff's recruits in Whittier, California, on Wednesday. (Jeff Gritchen/The Orange County Register via AP)

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The California Highway Patrol is also investigating the collision. Those with any information related to the incident should call the Los Angeles County Sheriff's Department's Homicide Bureau at 323-890-5500.

Fox News Digital's Greg Norman contributed to this report.