diff --git a/inmail.services.yml b/inmail.services.yml
index 58583ca..4ef5986 100644
--- a/inmail.services.yml
+++ b/inmail.services.yml
@@ -1,7 +1,7 @@
 services:
   inmail.processor:
     class: Drupal\inmail\MessageProcessor
-    arguments: ['@entity.manager', '@plugin.manager.inmail.analyzer', '@plugin.manager.inmail.handler', '@logger.channel.inmail', '@inmail.mime_parser']
+    arguments: ['@entity.manager', '@plugin.manager.inmail.analyzer', '@plugin.manager.inmail.handler', '@logger.channel.inmail', '@inmail.mime_parser', '@account_switcher']
   plugin.manager.inmail.deliverer:
     class: Drupal\Core\Plugin\DefaultPluginManager
     arguments:
diff --git a/src/MessageProcessor.php b/src/MessageProcessor.php
index 04a38fe..d41d1de 100644
--- a/src/MessageProcessor.php
+++ b/src/MessageProcessor.php
@@ -5,6 +5,7 @@ namespace Drupal\inmail;
 use Drupal\Component\Utility\SafeMarkup;
 use Drupal\Core\Entity\EntityManagerInterface;
 use Drupal\Core\Logger\LoggerChannelInterface;
+use Drupal\Core\Session\AccountSwitcherInterface;
 use Drupal\inmail\Entity\DelivererConfig;
 use Drupal\inmail\MIME\ParseException;
 use Drupal\inmail\MIME\ParserInterface;
@@ -62,15 +63,23 @@ class MessageProcessor implements MessageProcessorInterface {
   protected $parser;
 
   /**
+   * The account switcher service.
+   *
+   * @var \Drupal\Core\Session\AccountSwitcherInterface
+   */
+  protected $accountSwitcher;
+
+  /**
    * Constructs a new message processor.
    */
-  public function __construct(EntityManagerInterface $entity_manager, AnalyzerManagerInterface $analyzer_manager, HandlerManagerInterface $handler_manager, LoggerChannelInterface $logger_channel, ParserInterface $parser) {
+  public function __construct(EntityManagerInterface $entity_manager, AnalyzerManagerInterface $analyzer_manager, HandlerManagerInterface $handler_manager, LoggerChannelInterface $logger_channel, ParserInterface $parser, AccountSwitcherInterface $account_switcher) {
     $this->analyzerStorage = $entity_manager->getStorage('inmail_analyzer');
     $this->analyzerManager = $analyzer_manager;
     $this->handlerStorage = $entity_manager->getStorage('inmail_handler');
     $this->handlerManager = $handler_manager;
     $this->loggerChannel = $logger_channel;
     $this->parser = $parser;
+    $this->accountSwitcher = $account_switcher;
   }
 
   /**
@@ -117,6 +126,13 @@ class MessageProcessor implements MessageProcessorInterface {
       $event and $event->addArgument(get_class($analyzer_result), $analyzer_result->summarize());
     }
 
+    // Conditionally switch to the account identified by analyzers.
+    $has_account_changed = FALSE;
+    if ($default_result->isUserAuthenticated()) {
+      $this->accountSwitcher->switchTo($default_result->getAccount());
+      $has_account_changed = TRUE;
+    }
+
     // Handle message.
     foreach ($this->handlerStorage->loadMultiple() as $handler_config) {
       /** @var \Drupal\inmail\Entity\HandlerConfig $handler_config */
@@ -127,6 +143,11 @@ class MessageProcessor implements MessageProcessorInterface {
       }
     }
 
+    if ($has_account_changed) {
+      // Switch back to a previous account.
+      $this->accountSwitcher->switchBack();
+    }
+
     if ($event) {
       // Dump all log items into a past argument per source.
       foreach ($result->readLog() as $source => $log) {
diff --git a/tests/modules/inmail_test/src/Plugin/inmail/Analyzer/TestAnalyzer.php b/tests/modules/inmail_test/src/Plugin/inmail/Analyzer/TestAnalyzer.php
index 12a8cc8..08a0c2e 100644
--- a/tests/modules/inmail_test/src/Plugin/inmail/Analyzer/TestAnalyzer.php
+++ b/tests/modules/inmail_test/src/Plugin/inmail/Analyzer/TestAnalyzer.php
@@ -8,6 +8,7 @@ use Drupal\inmail\DefaultAnalyzerResult;
 use Drupal\inmail\MIME\MessageInterface;
 use Drupal\inmail\Plugin\inmail\Analyzer\AnalyzerBase;
 use Drupal\inmail\ProcessorResultInterface;
+use Drupal\user\Entity\User;
 
 /**
  * Provides a test analyzer.
@@ -28,6 +29,17 @@ class TestAnalyzer extends AnalyzerBase {
 
     // Provide sample context.
     $this->addContext($default_result);
+
+    // Update default result with example account.
+    $users = \Drupal::entityTypeManager()->getStorage('user')->loadByProperties(['mail' => 'demo@example.com']);
+    if (!$demo_user = reset($users)) {
+      $demo_user = User::create([
+        'mail' => 'demo@example.com',
+        'name' => 'Demo User',
+      ]);
+      $demo_user->save();
+    }
+    $default_result->setAccount($demo_user);
   }
 
   /**
diff --git a/tests/modules/inmail_test/src/Plugin/inmail/Handler/ResultKeeperHandler.php b/tests/modules/inmail_test/src/Plugin/inmail/Handler/ResultKeeperHandler.php
index 1aa1734..98abcf4 100644
--- a/tests/modules/inmail_test/src/Plugin/inmail/Handler/ResultKeeperHandler.php
+++ b/tests/modules/inmail_test/src/Plugin/inmail/Handler/ResultKeeperHandler.php
@@ -30,6 +30,7 @@ class ResultKeeperHandler extends HandlerBase {
   public function invoke(MessageInterface $message, ProcessorResultInterface $processor_result) {
     \Drupal::state()->set('inmail_test.result_keeper.message', $message);
     \Drupal::state()->set('inmail_test.result_keeper.result', $processor_result);
+    \Drupal::state()->set('inmail_test.result_keeper.account_name', \Drupal::currentUser()->getDisplayName());
   }
 
   /**
@@ -52,4 +53,14 @@ class ResultKeeperHandler extends HandlerBase {
     return \Drupal::state()->get('inmail_test.result_keeper.result');
   }
 
+  /**
+   * Returns the account display name.
+   *
+   * @return string
+   *   The account display name.
+   */
+  public static function getAccountName() {
+    return \Drupal::state()->get('inmail_test.result_keeper.account_name');
+  }
+
 }
diff --git a/tests/src/Kernel/AnalyzerTest.php b/tests/src/Kernel/AnalyzerTest.php
index f4f6e31..9a2b359 100644
--- a/tests/src/Kernel/AnalyzerTest.php
+++ b/tests/src/Kernel/AnalyzerTest.php
@@ -25,13 +25,16 @@ class AnalyzerTest extends KernelTestBase {
    *
    * @var array
    */
-  public static $modules = array('inmail', 'inmail_test', 'user');
+  public static $modules = array('inmail', 'inmail_test', 'user', 'system');
 
   /**
    * {@inheritdoc}
    */
   protected function setUp() {
     parent::setUp();
+    $this->installSchema('system', ['sequences']);
+    $this->installSchema('user', ['users_data']);
+    $this->installEntitySchema('user');
     $this->installConfig(['inmail']);
     \Drupal::configFactory()->getEditable('inmail.settings')
       ->set('return_path', 'bounces@example.com')
@@ -87,7 +90,7 @@ EOF;
 
     $this->assertEqual($result->getRecipient(), 'verp-parsed@example.org');
 
-    $this->assertEquals(User::getAnonymousUser()->id(), $default_result->getAccount()->id());
+    $this->assertEquals('Demo User', $default_result->getAccount()->getDisplayName());
     $this->assertEquals('Sample context value', $default_result->getContext('test')->getContextValue());
 
     // Adding already defined context should throw exception.
diff --git a/tests/src/Kernel/ProcessorTest.php b/tests/src/Kernel/ProcessorTest.php
index e756c4a..e203425 100644
--- a/tests/src/Kernel/ProcessorTest.php
+++ b/tests/src/Kernel/ProcessorTest.php
@@ -2,7 +2,11 @@
 
 namespace Drupal\Tests\inmail\Kernel;
 
+use Drupal\inmail\DefaultAnalyzerResult;
+use Drupal\inmail\Entity\AnalyzerConfig;
 use Drupal\inmail\Entity\DelivererConfig;
+use Drupal\inmail\Entity\HandlerConfig;
+use Drupal\inmail_test\Plugin\inmail\Handler\ResultKeeperHandler;
 use Drupal\KernelTests\KernelTestBase;
 
 /**
@@ -12,11 +16,14 @@ use Drupal\KernelTests\KernelTestBase;
  */
 class ProcessorTest extends KernelTestBase {
 
-  public static $modules = array('inmail', 'inmail_test', 'dblog');
+  public static $modules = array('inmail', 'inmail_test', 'dblog', 'user', 'system');
 
   protected function setUp() {
     parent::setUp();
+    $this->installSchema('system', ['sequences']);
+    $this->installSchema('user', ['users_data']);
     $this->installSchema('dblog', ['watchdog']);
+    $this->installEntitySchema('user');
   }
 
   /**
@@ -39,4 +46,33 @@ class ProcessorTest extends KernelTestBase {
     $this->assertEqual('Unable to process message, parser failed with message "@message"', $dblog_entry['message']);
   }
 
+  /**
+   * Tests account switching mechanism.
+   */
+  public function testAccountSwitching() {
+    $raw = <<<EOF
+Subject: Hello!
+From: Demo User <demo@example.com>
+To: receiver@example.com
+
+Hello world!
+EOF;
+
+    /** @var \Drupal\inmail\MessageProcessorInterface $processor */
+    $processor = \Drupal::service('inmail.processor');
+
+    AnalyzerConfig::create(['id' => 'test_analyzer', 'plugin' => 'test_analyzer'])->save();
+    HandlerConfig::create(['id' => 'result_keeper', 'plugin' => 'result_keeper'])->save();
+    $processor->process($raw, DelivererConfig::create(['id' => 'test']));
+
+    $processor_result = ResultKeeperHandler::getResult();
+    /** @var \Drupal\inmail\DefaultAnalyzerResult $default_result */
+    $default_result = $processor_result->getAnalyzerResult(DefaultAnalyzerResult::TOPIC);
+
+    // Assert "Test Analyzer" updated the account on default result.
+    $this->assertEquals('Demo User', $default_result->getAccount()->getDisplayName());
+    // Assert the account was switched on handler's level.
+    $this->assertEquals('Demo User', ResultKeeperHandler::getAccountName());
+  }
+
 }