A sheriff's deputy from San Joaquin County is on administrative leave after hitting and killing someone with a sheriff's department vehicle this morning.

The deputy is part of a special unit with the San Joaquin Sheriff's Department and the van he was driving is unmarked.

"We've invoked a multi-agency protcol investigation which involves the district attorney's office, our office, as well as the Stockton Police Department," San Joaquin County Sheriff's spokesman Les Garcia said. 

Garcia says the deputy was on duty at the time, but won't say what his assignment was.  

The victim was an older man who was in the street at the time of the accident.  

Garcia says there is no crosswalk at the intersection where this happened.  

It's expected the deputy will return from the paid leave in three days.

Stay tuned to NewsRadio KFBK and KFBK for updates on this developing story.