diff --git a/spec/test-utils.js b/spec/test-utils.js
index e5d5c490b..111c032a3 100644
--- a/spec/test-utils.js
+++ b/spec/test-utils.js
@@ -85,6 +85,7 @@ export function mkEvent(opts) {
         room_id: opts.room,
         sender: opts.sender || opts.user, // opts.user for backwards-compat
         content: opts.content,
+        unsigned: opts.unsigned,
         event_id: "$" + Math.random() + "-" + Math.random(),
     };
     if (opts.skey !== undefined) {
diff --git a/spec/unit/filter-component.spec.js b/spec/unit/filter-component.spec.js
index 49f1d5614..d5d9fa287 100644
--- a/spec/unit/filter-component.spec.js
+++ b/spec/unit/filter-component.spec.js
@@ -1,3 +1,4 @@
+import { RelationType, UNSTABLE_FILTER_RELATION_SENDERS, UNSTABLE_FILTER_RELATION_TYPES } from "../../src";
 import { FilterComponent } from "../../src/filter-component";
 import { mkEvent } from '../test-utils';
 
@@ -30,5 +31,98 @@ describe("Filter Component", function() {
 
             expect(checkResult).toBe(true);
         });
+
+        it("should filter out events by relation participation", function() {
+            const currentUserId = '@me:server.org';
+            const filter = new FilterComponent({
+                [UNSTABLE_FILTER_RELATION_SENDERS.name]: currentUserId,
+            }, currentUserId);
+
+            const threadRootNotParticipated = mkEvent({
+                type: 'm.room.message',
+                content: {},
+                room: 'roomId',
+                user: '@someone-else:server.org',
+                event: true,
+                unsigned: {
+                    "m.relations": {
+                        [RelationType.Thread]: {
+                            count: 2,
+                            current_user_participated: false,
+                        },
+                    },
+                },
+            });
+
+            expect(filter.check(threadRootNotParticipated)).toBe(false);
+        });
+
+        it("should keep events by relation participation", function() {
+            const currentUserId = '@me:server.org';
+            const filter = new FilterComponent({
+                [UNSTABLE_FILTER_RELATION_SENDERS.name]: currentUserId,
+            }, currentUserId);
+
+            const threadRootParticipated = mkEvent({
+                type: 'm.room.message',
+                content: {},
+                unsigned: {
+                    "m.relations": {
+                        [RelationType.Thread]: {
+                            count: 2,
+                            current_user_participated: true,
+                        },
+                    },
+                },
+                user: '@someone-else:server.org',
+                room: 'roomId',
+                event: true,
+            });
+
+            expect(filter.check(threadRootParticipated)).toBe(true);
+        });
+
+        it("should filter out events by relation type", function() {
+            const filter = new FilterComponent({
+                [UNSTABLE_FILTER_RELATION_TYPES.name]: RelationType.Thread,
+            });
+
+            const referenceRelationEvent = mkEvent({
+                type: 'm.room.message',
+                content: {},
+                room: 'roomId',
+                event: true,
+                unsigned: {
+                    "m.relations": {
+                        [RelationType.Reference]: {},
+                    },
+                },
+            });
+
+            expect(filter.check(referenceRelationEvent)).toBe(false);
+        });
+
+        it("should keep events by relation type", function() {
+            const filter = new FilterComponent({
+                [UNSTABLE_FILTER_RELATION_TYPES.name]: RelationType.Thread,
+            });
+
+            const threadRootEvent = mkEvent({
+                type: 'm.room.message',
+                content: {},
+                unsigned: {
+                    "m.relations": {
+                        [RelationType.Thread]: {
+                            count: 2,
+                            current_user_participated: true,
+                        },
+                    },
+                },
+                room: 'roomId',
+                event: true,
+            });
+
+            expect(filter.check(threadRootEvent)).toBe(true);
+        });
     });
 });
diff --git a/src/filter-component.ts b/src/filter-component.ts
index 9ef535558..a69b9f454 100644
--- a/src/filter-component.ts
+++ b/src/filter-component.ts
@@ -80,9 +80,10 @@ export class FilterComponent {
         // of performance
         // This should be improved when bundled relationships solve that problem
         const relationSenders = [];
-        if (this.userId && relations?.[RelationType.Thread]?.current_user_participated) {
+        if (this.userId && bundledRelationships?.[RelationType.Thread]?.current_user_participated) {
             relationSenders.push(this.userId);
         }
+
         return this.checkFields(
             event.getRoomId(),
             event.getSender(),