SAN FRANCISCO—A six-week-long investigation resulted in an arrest warrant for San Francisco Sherriff Deputy Michael R. Lewelling, 33, who surrendered to authorities on December 19, for the alleged assault of an emergency room patient and then filing a fictitious police report.

Lewelling is facing four felony charges including perjury and assault, and one charge of misdemeanor battery, according to San Francisco District Attorney George Gascón.

On November 3, Lewelling was assigned to a Sheriff’s Department’s patrol unit at the San Francisco General Hospital, where video surveillance allegedly captured evidence that proves Lewelling’s police report to be dishonest.

The surveillance footage reportedly shows a patient hunched over, sleeping in a chair in the emergency room at around 5:00 a.m. on November 3. Lewelling then approaches the patient, wakes him up and initiates a conversation. When the patient tries to walk away with the help of a wooden cane, Lewelling allegedly grabs the back of his collar and forces the victim back in his chair—and kicks away his cane.

Lewelling then reportedly put the victim in a chokehold and proceeding to arrest him.

That same day, the San Francisco District Attorney’s Office, reviewing the case, declined to make any charges against the patient and instead made a request for the video footage, which validated their suspicions.

Lewelling argues in the police report that he was the victim and that the patient had assaulted him with his cane.

Lewelling paid his $138,000 bail on December 20 and was subsequently released.

“The fact that a Sheriff’s Deputy allegedly battered a patient at San Francisco General Hospital is unnerving,” said  San Francisco District Attorney George Gascón. “What’s worse is that he’s also alleged to have perjured himself on a police report, unforgivable conduct that led to the arrest of the innocent victim.”