diff --git a/tools/filesystem/filesystem.go b/tools/filesystem/filesystem.go
index 128861e6..b3a3bc0c 100644
--- a/tools/filesystem/filesystem.go
+++ b/tools/filesystem/filesystem.go
@@ -8,7 +8,6 @@ import (
 	"mime/multipart"
 	"net/http"
 	"os"
-	"path"
 	"path/filepath"
 	"regexp"
 	"sort"
@@ -276,6 +275,8 @@ func (s *System) Delete(fileKey string) error {
 }
 
 // DeletePrefix deletes everything starting with the specified prefix.
+//
+// The prefix could be subpath (ex. "/a/b/") or filename prefix (ex. "/a/b/file_").
 func (s *System) DeletePrefix(prefix string) []error {
 	failed := []error{}
 
@@ -285,7 +286,14 @@ func (s *System) DeletePrefix(prefix string) []error {
 	}
 
 	dirsMap := map[string]struct{}{}
-	dirsMap[prefix] = struct{}{}
+
+	var isPrefixDir bool
+
+	// treat the prefix as directory only if it ends with trailing slash
+	if strings.HasSuffix(prefix, "/") {
+		isPrefixDir = true
+		dirsMap[strings.TrimRight(prefix, "/")] = struct{}{}
+	}
 
 	// delete all files with the prefix
 	// ---
@@ -303,8 +311,11 @@ func (s *System) DeletePrefix(prefix string) []error {
 
 		if err := s.Delete(obj.Key); err != nil {
 			failed = append(failed, err)
-		} else {
-			dirsMap[path.Dir(obj.Key)] = struct{}{}
+		} else if isPrefixDir {
+			slashIdx := strings.LastIndex(obj.Key, "/")
+			if slashIdx > -1 {
+				dirsMap[obj.Key[:slashIdx]] = struct{}{}
+			}
 		}
 	}
 	// ---
diff --git a/tools/filesystem/filesystem_test.go b/tools/filesystem/filesystem_test.go
index 7b57b549..57e880ca 100644
--- a/tools/filesystem/filesystem_test.go
+++ b/tools/filesystem/filesystem_test.go
@@ -101,7 +101,7 @@ func TestFileSystemDelete(t *testing.T) {
 	}
 }
 
-func TestFileSystemDeletePrefix(t *testing.T) {
+func TestFileSystemDeletePrefixWithoutTrailingSlash(t *testing.T) {
 	dir := createTestDir(t)
 	defer os.RemoveAll(dir)
 
@@ -115,7 +115,7 @@ func TestFileSystemDeletePrefix(t *testing.T) {
 		t.Fatal("Expected error, got nil", errs)
 	}
 
-	if errs := fs.DeletePrefix("missing/"); len(errs) != 0 {
+	if errs := fs.DeletePrefix("missing"); len(errs) != 0 {
 		t.Fatalf("Not existing prefix shouldn't error, got %v", errs)
 	}
 
@@ -123,13 +123,50 @@ func TestFileSystemDeletePrefix(t *testing.T) {
 		t.Fatalf("Expected nil, got errors %v", errs)
 	}
 
-	// ensure that the test/ files are deleted
+	// ensure that the test/* files are deleted
 	if exists, _ := fs.Exists("test/sub1.txt"); exists {
 		t.Fatalf("Expected test/sub1.txt to be deleted")
 	}
 	if exists, _ := fs.Exists("test/sub2.txt"); exists {
 		t.Fatalf("Expected test/sub2.txt to be deleted")
 	}
+
+	// the test directory should remain since the prefix didn't have trailing slash
+	if _, err := os.Stat(filepath.Join(dir, "test")); os.IsNotExist(err) {
+		t.Fatal("Expected the prefix dir to remain")
+	}
+}
+
+func TestFileSystemDeletePrefixWithTrailingSlash(t *testing.T) {
+	dir := createTestDir(t)
+	defer os.RemoveAll(dir)
+
+	fs, err := filesystem.NewLocal(dir)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer fs.Close()
+
+	if errs := fs.DeletePrefix("missing/"); len(errs) != 0 {
+		t.Fatalf("Not existing prefix shouldn't error, got %v", errs)
+	}
+
+	if errs := fs.DeletePrefix("test/"); len(errs) != 0 {
+		t.Fatalf("Expected nil, got errors %v", errs)
+	}
+
+	// ensure that the test/* files are deleted
+	if exists, _ := fs.Exists("test/sub1.txt"); exists {
+		t.Fatalf("Expected test/sub1.txt to be deleted")
+	}
+	if exists, _ := fs.Exists("test/sub2.txt"); exists {
+		t.Fatalf("Expected test/sub2.txt to be deleted")
+	}
+
+	// the test directory should be also deleted since the prefix has trailing slash
+	if _, err := os.Stat(filepath.Join(dir, "test")); !os.IsNotExist(err) {
+		t.Fatal("Expected the prefix dir to be deleted")
+	}
 }
 
 func TestFileSystemUploadMultipart(t *testing.T) {