Additional warrants were served on the homes of the city manager and fire chief in Colorado City.
Management of the twin towns, the FLDS and its religious traditions have been under increasing scrutiny since 2005, following allegations of an increase in underage marriages and misuse of church funds.
The scope of the warrants was unclear, said Parker, adding he had not yet seen the documents.
Residents said there appeared to be at least 10 marked police cars and other unmarked cars in the communities when the documents were delivered.
Mohave County sheriff's office spokeswoman Trish Carter said she could only confirm department personnel were in the Arizona community.
In Utah, Washington County Undersheriff Jake Adams said several of his officers were assisting Arizona authorities.