diff --git a/internal/engine/engine.go b/internal/engine/engine.go
index 529d4e6..ece2c36 100644
--- a/internal/engine/engine.go
+++ b/internal/engine/engine.go
@@ -20,7 +20,7 @@ type Engine struct {
 	indexMgr IndexManager
 
 	// `library` is a "set" that stores documents names to avoid adding the same document multiple times.
-	library map[string]struct{}
+	library map[string]int
 
 	// `processor` is used to process the tokens before adding them to the index and before querying the index,
 	// it removes stop words and apply stemming and normalization to the tokens.
@@ -34,19 +34,26 @@ func NewEngine(processor textprocessing.Processor, delimiterManager *tokenizer.D
 	return &Engine{
 		docs:             make([]*internal.Document, 0),
 		indexMgr:         idxMgr,
-		library:          make(map[string]struct{}),
+		library:          make(map[string]int),
 		processor:        processor,
 		delimiterManager: delimiterManager,
 	}
 }
 
 func (e *Engine) AddDocument(doc *internal.Document) {
-	if _, ok := e.library[doc.Name]; !ok {
-		doc.ID = e.GetNextDocID()
+	if _, ok := e.library[doc.GetFilePath()]; !ok {
+		logger.Info(EnginePrefix, "Adding document %s", doc.GetFilePath())
+
+        doc.ID = e.GetNextDocID()
 		e.docs = append(e.docs, doc)
-		e.library[doc.DirectoryPath] = struct{}{}
-		e.parseDocument(doc)
+		e.library[doc.GetFilePath()] = doc.ID
+	} else { // document already exists, update the document by removing it from the index and re-adding it
+		logger.Warn(EnginePrefix, "Updating document %s", doc.GetFilePath())
+
+        doc.ID = e.library[doc.GetFilePath()]
+        e.indexMgr.Remove(doc.ID)
 	}
+    e.parseDocument(doc)
 }
 
 func (e *Engine) ProcessToken(token string) string {
diff --git a/internal/engine/index_manager.go b/internal/engine/index_manager.go
index 6f6fab9..49a63fa 100644
--- a/internal/engine/index_manager.go
+++ b/internal/engine/index_manager.go
@@ -37,6 +37,20 @@ func (idx *IndexManager) PutSlice(key string, values []int) {
 	}
 }
 
+func (idx *IndexManager) Remove(docID int) {
+	logger.Info(IndexManagerPrefix, fmt.Sprintf("Removing document ID %d from index, A LINEAR SEARCH is performed.", docID))
+
+	numRemove := 0
+
+	for key := range idx.index {
+		if idx.index[key].Remove(docID) {
+			numRemove++
+		}
+	}
+
+    logger.Info(IndexManagerPrefix, fmt.Sprintf("Removed document ID %d, %d Keys are affected.", docID, numRemove))
+}
+
 func (idx *IndexManager) Get(key string) ordered.OrderedStructure[int] {
 	if _, ok := idx.index[key]; !ok {
 		logger.Warn(IndexManagerPrefix, fmt.Sprintf("Key %s not found in index", key))
diff --git a/internal/structures/ordered/ordered_slice.go b/internal/structures/ordered/ordered_slice.go
index 1d10904..03d6474 100644
--- a/internal/structures/ordered/ordered_slice.go
+++ b/internal/structures/ordered/ordered_slice.go
@@ -32,11 +32,11 @@ func NewOrderedSliceWithSlice[Entry constraints.Integer](slice []Entry) OrderedS
 	return &OrderedSlice[Entry]{data: newSlice}
 }
 
-func (o *OrderedSlice[Entry]) InsertSorted(entry Entry) {
+func (o *OrderedSlice[Entry]) InsertSorted(entry Entry) bool {
 	var idx = o.UpperBound(entry)
 
 	if idx-1 >= 0 && o.data[idx-1] == entry { // neglect duplicates
-		return
+		return false
 	}
 
 	o.data = append(o.data, entry)
@@ -45,6 +45,8 @@ func (o *OrderedSlice[Entry]) InsertSorted(entry Entry) {
 	for i := idx + 1; i < len(o.data); i++ {
 		o.data[i], swp = swp, o.data[i]
 	}
+
+    return true;
 }
 
 func (o *OrderedSlice[Entry]) BinarySearch(entry Entry) int {
@@ -194,3 +196,17 @@ func (s1 *OrderedSlice[Entry]) Union(s2 OrderedStructure[Entry]) OrderedStructur
 
 	return res
 }
+
+func (s *OrderedSlice[Entry]) Remove(entry Entry) bool {
+    if s == nil || s.IsEmpty() {
+        return false
+    }
+
+    var idx = s.BinarySearch(entry)
+    if idx == -1 {
+        return false
+    }
+
+    s.data = append(s.data[:idx], s.data[idx+1:]...)
+    return true
+}
diff --git a/internal/structures/ordered/ordered_structure.go b/internal/structures/ordered/ordered_structure.go
index 9bd110c..36e186e 100644
--- a/internal/structures/ordered/ordered_structure.go
+++ b/internal/structures/ordered/ordered_structure.go
@@ -11,7 +11,8 @@ type SetOperations[Entry constraints.Ordered] interface {
 type OrderedStructure[Entry constraints.Ordered] interface {
 	SetOperations[Entry]
 
-	InsertSorted(Entry)
+	InsertSorted(Entry) bool
+    Remove(Entry) bool
 
 	GetLength() int
 	IsEmpty() bool
diff --git a/internal/structures/ordered/skip_pointer_list.go b/internal/structures/ordered/skip_pointer_list.go
index 0d97c20..6f45dbd 100644
--- a/internal/structures/ordered/skip_pointer_list.go
+++ b/internal/structures/ordered/skip_pointer_list.go
@@ -84,23 +84,21 @@ func (s *SkipPointerList[Entry]) UpdateSkipPointers() {
 	}
 }
 
-func (s *SkipPointerList[Entry]) InsertSorted(entry Entry) {
+func (s *SkipPointerList[Entry]) InsertSorted(entry Entry) bool {
 	newNode := &SkipNode[Entry]{entry: entry}
 	if s.head == nil {
 		s.head = newNode
 		s.tail = newNode
 		s.size++
-		return
+		return true
 	}
 
 	if s.head.entry > entry {
-		s.pushFront(entry)
-		return
+		return s.pushFront(entry)
 	}
 
 	if s.tail.entry < entry {
-		s.pushBack(entry)
-		return
+		return s.pushBack(entry)
 	}
 
 	curr := s.head
@@ -114,7 +112,7 @@ func (s *SkipPointerList[Entry]) InsertSorted(entry Entry) {
 
 	// neglect duplicates
 	if curr.next != nil && curr.next.entry == entry {
-		return
+		return false
 	}
 
 	newNode.next = curr.next
@@ -129,6 +127,8 @@ func (s *SkipPointerList[Entry]) InsertSorted(entry Entry) {
 	if s.size >= (s.currBlockSize+1)*(s.currBlockSize+1) {
 		s.UpdateSkipPointers()
 	}
+
+	return true
 }
 
 func (s *SkipPointerList[Entry]) GetLength() int {
@@ -141,10 +141,9 @@ func (s *SkipPointerList[Entry]) IsEmpty() bool {
 
 // Used internally for `SetOperations` functions,
 // where it is guaranteed that the insertion is always sorted and added to the end
-func (s *SkipPointerList[Entry]) pushBack(entry Entry) {
+func (s *SkipPointerList[Entry]) pushBack(entry Entry) bool {
 	if s.IsEmpty() {
-		s.InsertSorted(entry)
-		return
+		return s.InsertSorted(entry)
 	}
 
 	if s.tail.entry > entry {
@@ -152,18 +151,19 @@ func (s *SkipPointerList[Entry]) pushBack(entry Entry) {
 	}
 
 	if s.tail.entry == entry {
-		return
+		return false
 	}
 
 	s.tail.next = &SkipNode[Entry]{entry: entry}
 	s.tail = s.tail.next
 	s.size++
+
+	return true
 }
 
-func (s *SkipPointerList[Entry]) pushFront(entry Entry) {
+func (s *SkipPointerList[Entry]) pushFront(entry Entry) bool {
 	if s.IsEmpty() {
-		s.InsertSorted(entry)
-		return
+		return s.InsertSorted(entry)
 	}
 
 	if s.head.entry < entry {
@@ -171,12 +171,14 @@ func (s *SkipPointerList[Entry]) pushFront(entry Entry) {
 	}
 
 	if s.head.entry == entry {
-		return
+		return false
 	}
 
 	newNode := &SkipNode[Entry]{entry: entry, next: s.head}
 	s.head = newNode
 	s.size++
+
+	return true
 }
 
 func (s *SkipPointerList[Entry]) At(index int) Entry {
@@ -285,3 +287,37 @@ func (s1 *SkipPointerList[Entry]) Union(s2 OrderedStructure[Entry]) OrderedStruc
 
 	return res
 }
+
+func (s *SkipPointerList[Entry]) Remove(entry Entry) bool {
+    if s.IsEmpty() {
+        return false
+    }
+
+    if s.head.entry == entry {
+        s.head = s.head.next
+        s.size--
+        return true
+    }
+
+    curr := s.head
+    for curr.next != nil && curr.next.entry < entry {
+        if curr.skip != nil && curr.skip.entry < entry {
+            curr = curr.skip
+        } else {
+            curr = curr.next
+        }
+    }
+
+    if curr.next == nil || curr.next.entry != entry {
+        return false
+    }
+
+    curr.next = curr.next.next
+    s.size--
+
+    if curr.next == nil {
+        s.tail = curr
+    }
+
+    return true
+}