Function for verifying local and domain users

usersearch.ps1

Function UserSearch
{
    Param ([string]$AccountName)
    #Check if there's a realm specified
    if ($AccountName.Split("\").count -gt 1)
    {
        if ($AccountName.Split("\")[0] -eq $env:COMPUTERNAME)
        {
            $IsLocalAccount = $true
        }
        Else
        {
            $IsDomainAccount = $true
            $IsUpn = $false
        }

    }
    Elseif ($AccountName -contains "@")
    {
        $IsDomainAccount = $true
        $IsUpn = $true
    }
    Else
    {
        #Default to local user account
        $accountname = $env:COMPUTERNAME + "\" + $AccountName
        $IsLocalAccount = $true
    }


    if ($IsLocalAccount -eq $true)
    {
        $localaccount = get-wmiobject -class "Win32_UserAccount" -namespace "root\CIMV2" -filter "(LocalAccount = True)" | where {$_.Caption -eq $AccountName}
        if ($localaccount)
        {
            return $localaccount.Caption
        }
        $LocalGroup = get-wmiobject -class "Win32_Group" -namespace "root\CIMV2" -filter "LocalAccount = True"| where {$_.Caption -eq $AccountName}
        if ($LocalGroup)
        {
            return $LocalGroup.Caption
        }
    }
    ElseIf (($IsDomainAccount -eq $true) -and ($IsUpn -eq $false))
    {
        #Search by samaccountname
        $Searcher = [adsisearcher]""
        $Searcher.Filter = "sAMAccountName=$($accountname.split("\")[1])"
        $result = $Searcher.FindOne()

        if ($result)
        {
            return $accountname
        }
    }

}