The District Attorney's Office filed charges Thursday against Twin Rivers Unified School District police Officer Branche Smith, accusing him of four misdemeanor counts of assault while on duty.

Smith, 37, is accused of choking two subjects who were detained at the Twin Rivers Police Department on Sept. 17, 2010. The subjects were handcuffed to benches.

During the same incident, Smith also is accused of threatening a third subject with a stun gun, according to a news release from the Sacramento County District Attorney's Office.

In a separate incident on May 30, 2011, Smith is accused of kicking a handcuffed subject in the head while the subject was on the floor at the Sacramento County jail.

Smith faces up to four years in jail and a fine of $10,000. Smith turned himself in on Thursday.

Smith's arrest comes as the Twin Rivers Police Department continues to make sweeping changes following intense scrutiny over the past eight months.

The department is the focus of a number of investigations – including by the Sacramento Police Department – into various accusations, including whether district officials ordered school police to conduct illegal background checks on hundreds of adult education students, as well as middle school and high school students.

The Sacramento County grand jury is expected to release its report soon on the school district and its police force. The panel issued a series of subpoenas seeking information on allegations of mishandling and theft of district property, as well as the temporary misplacement of an automatic weapon, according to sources familiar with the investigation.

Twin Rivers Police Chief Christopher Breck was placed on paid administrative leave in November and a series of other officers have since resigned or been placed on leave.

Twin Rivers Acting Police Chief Scott LaCosse said the allegations against Smith were first brought to the attention of previous leaders in the department.

"I fully understand people will look at this and be concerned," LaCosse said. "These incidents happened quite some time in the past. There were people who tried to address this and when given a second opportunity worked to get it resolved."

Smith was initially placed on leave in January for an unrelated matter, which LaCosse said he could not discuss due to privacy laws.

LaCosse said 15 minutes after Smith was placed on leave, four other officers in the department came forward with the allegations that led to his current charges.

"This fell on deaf ears to previous management," LaCosse said. "I'm under the impression little to no action was taken. He was driving out of the parking lot when the officers came forward. They were waiting to see if their concerns would be taken seriously this time."

LaCosse said the information was turned over immediately to the Sacramento Police Department, which is investigating the school district's police force and related staff.

LaCosse said Smith was the only officer involved in the incidents leading to the four assault charges under the color of authority.

Smith has been a school district police officer since 2002.

© Copyright The Sacramento Bee. All rights reserved.

• Read more articles by Melody Gutierrez

Order Reprint