C# DataReader associated with this Connection which must be closed first

Question

I am trying to create a c# application which tries to connect and query the MySql Database. Below is the piece of code that I am using

public static void ValidateName(MySqlConnection conn,List<Employee> EmpList, string Group)
 {
 string selectQuery = "Select Name from Employee where Group = @Group  AND @Name in (FirstName, LastName);";
 using (MySqlCommand cmd = new MySqlCommand(selectQuery, conn))
 cmd.Parameters.Add(new MySqlParameter("@Group", MySqlDbType.VarChar));
 cmd.Parameters.Add(new MySqlParameter("@Name", MySqlDbType.VarChar));
 for (int i = 0; i < EmpList.Count; i++)
 {
    cmd.Parameters["@Group"].Value = Group;
    cmd.Parameters["@Name"].Value = EmpList[i].Name;
    var reader = cmd.ExecuteReader();
    List<string> lineList = new List<string>();
    while (reader.Read())
    {
        lineList.Add(reader.GetString(0));
    }
    if (lineList.Count <=0)
    {
       WriteValidationFailure(EmpList[i], "Failed");
    }}

It now throws error in the statement

    var reader = cmd.ExecuteReader();