Trinette Marquis with the Department says LaCosse spent three years as Commander of the area that includes the Twin Rivers district.
MARQUIS: "It's not ideal to have the number of transitions that we've had in the leadership of the department. So, one of the things that we could do is make sure this person had ties to the community, understood the community as well."
Chief Christopher Breck has been on paid administrative leave since November pending the results of that investigation.
Marquis says some information obtained in that investigation has been turned over to the Bureau of Alcohol Tobacco Firearms and Explosives and the Sacramento County District Attorney's Office.
Acting Chief LaCosse will appear on the Capital Public Radio program, "Insight" on Monday at 10 a.m.