An internal investigation will review last week's high-speed chase involving Sheriff Al Cannon "in its entirety" and determine whether policies were violated, officials said Tuesday.
The pursuit spanned 25 miles, reached speeds of more than 120 mph and ended with Cannon and two deputies shooting out the tires of Timothy Shawn McManus' Dodge pickup truck.
It also included police video showing that a police dog was allowed to chew on McManus for 23 seconds after several officers had him on the ground.
Cannon and other spokesmen for the Charleston County Sheriff's Office have been reticent about the Jan. 30 pursuit since the sheriff acknowledged slapping the 31-year-old McManus after he was handcuffed.
Publicly, the admission has prompted some area residents to commend Cannon, while others started an online petition calling for his resignation.
"The sheriff's office is ... conducting an internal investigation to review this incident in its entirety, which includes reviewing its policies and procedures," Capt. Eric Watson, the sheriff's criminal investigations commander, said Tuesday. "Until these investigations have concluded, it would be inappropriate for me to comment any further."
Some of the procedures in question deal with vehicle pursuits, the use of police dogs and the approach to conducting a "high-risk" traffic stop.
The policies prohibit the use of unmarked cruisers during chases unless in cases of imminent risk to human life. Lt. Ransom Williams, a supervisor in an unmarked Dodge Charger, was the one who had taken control of the chase when it ended on Steed Creek Road.
They also state that a police dog should be used against a suspect when it "reasonably appears necessary to apprehend or secure" him. A video of McManus' arrest appears to show him subdued by several deputies when a dog bites him.
The Sheriff's Office said he was continuing to resist and later tried to spit on deputies.
A separate procedural guideline also instructs deputies making a "high-risk" traffic stop to take cover, then order a driver to drop the keys out the window, get out and drop to the ground.
After McManus' pickup went off the road, he got out. He was immediately punched by Williams, who had been approaching McManus with his handgun drawn.
Williams pulled him down and continued to hit him as other deputies joined in subduing him. It is unknown what was said between Williams and McManus because the video has no audio.
Asked to explain whether any of the guidelines were broken, sheriff's officials have repeatedly declined to comment. They cited ongoing investigations by the State Law Enforcement Division.
Kathryn Richardson, a spokeswoman for SLED, refused to discuss exactly what the agency would investigate. The chase has involved the allegations of abuse and the question of whether the use of deadly force was appropriate when deputies fired at McManus' pickup, which is typically investigated by SLED.
Cannon, who started the chase in his personal vehicle when he saw McManus' pickup traveling erratically, has insisted that his actions and those of his deputies were justified because McManus was putting other lives in danger.
Geoff Alpert, a criminal justice professor at the University of South Carolina, said the Sheriff's Office should ask an outside agency to review its policies.
"When you're dealing with a boss, who's an elected official, a different agency should do the job," he said. "It would be difficult for internal affairs."