Remove an item from SPFieldLookupValueCollection

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C#

SharePoint2010

SharePoint2013

I have a multilookup column "Employee". i wanted to remove one value from the column if some specific condtion is true. Below is the code:

public override void ItemUpdated(SPItemEventProperties properties)
{
    base.ItemUpdated(properties);
    using (SPWeb web = properties.OpenWeb())
    {
        SPList TestA = web.Lists["TestA"];
        string employee = Convert.ToString(properties.ListItem["EmployeeNo"]);
        string department = Convert.ToString(properties.AfterProperties["Department"]);
        int ItemID = properties.ListItem.ID;
        SPList TestB = web.Lists["TestB"];
        SPQuery query = new SPQuery();
        query.Query = "<Where><Eq><FieldRef Name='Department' /><Value Type='Text'>" + department + "</Value></Eq></Where>";
        SPListItemCollection items = TestB.GetItems(query);
        if (items.Count > 0)
        {
            foreach (SPListItem Item in items)
            {
                web.AllowUnsafeUpdates = true;
                SPFieldLookupValueCollection objLookupFieldValueCol = (SPFieldLookupValueCollection)Item["Employee"];
                SPFieldLookupValue lookupValue = new SPFieldLookupValue();
                lookupValue.LookupId = ItemID;
                objLookupFieldValueCol.Remove(lookupValue);
                Item["Employee"] = objLookupFieldValueCol;
                Item.Update();
                web.AllowUnsafeUpdates = false;
            }
        }
        else
        {
            //SPListItem NewlistItem = TestB.AddItem();
            SPFieldLookupValue lookupValue = new SPFieldLookupValue();
            lookupValue.LookupId = ItemID;
            SPFieldLookupValueCollection objLookupFieldValueCol = new SPFieldLookupValueCollection();
            objLookupFieldValueCol.Remove(lookupValue);

            //NewlistItem["Employee"] = objLookupFieldValueCol;
            //NewlistItem["Department"] = department;

            //NewlistItem.Update();
        }
        web.AllowUnsafeUpdates = false;
    }
}

it is not removing any value from the lookup column.