powershell update Peoplepicker in List In SHarePoint

#Read the CSV file 

#stored local variable 

$delimitercsv = "|" 

$filePath = "C:\peakfinders.csv" 

$userid = "EmpID"

$useremailowner = "Owner"

#Get the SharePoint List

$tWeb = Get-SPWeb -identity "http://sharepoint.peakfinders.com" 

$list = $tWeb.Lists["Employee"]

$CSVData = Import-CSV -path $filepath | ForEach-Object {

    Write-Host "$($_.ID) ,$($_.'Email-Address')";

foreach($sitem in $items)

{

$userid = $sitem['EmpID']

if($userid.LookUPid -eq $($_.ID)){

$sitem["mail"] =$($_.'Email-Address');

$sitem.Update()

}

}

}