diff --git a/cncd/queue/fifo.go b/cncd/queue/fifo.go
index 18cf328f5..f6c064b2a 100644
--- a/cncd/queue/fifo.go
+++ b/cncd/queue/fifo.go
@@ -99,41 +99,57 @@ func (q *fifo) Poll(c context.Context, f Filter) (*Task, error) {
 
 // Done signals that the item is done executing.
 func (q *fifo) Done(c context.Context, id string, exitStatus string) error {
-	return q.finished(id, exitStatus, nil)
+	return q.finished([]string{id}, exitStatus, nil)
 }
 
 // Error signals that the item is done executing with error.
 func (q *fifo) Error(c context.Context, id string, err error) error {
+	return q.finished([]string{id}, StatusFailure, err)
+}
+
+// Error signals that the item is done executing with error.
+func (q *fifo) ErrorAtOnce(c context.Context, id []string, err error) error {
 	return q.finished(id, StatusFailure, err)
 }
 
-func (q *fifo) finished(id string, exitStatus string, err error) error {
+func (q *fifo) finished(ids []string, exitStatus string, err error) error {
 	q.Lock()
-	taskEntry, ok := q.running[id]
-	if ok {
-		taskEntry.error = err
-		close(taskEntry.done)
-		delete(q.running, id)
-	} else {
-		q.removeFromPending(id)
+
+	for _, id := range ids {
+		taskEntry, ok := q.running[id]
+		if ok {
+			taskEntry.error = err
+			close(taskEntry.done)
+			delete(q.running, id)
+		} else {
+			q.removeFromPending(id)
+		}
+		q.updateDepStatusInQueue(id, exitStatus)
 	}
-	q.updateDepStatusInQueue(id, exitStatus)
+
 	q.Unlock()
 	return nil
 }
 
 // Evict removes a pending task from the queue.
 func (q *fifo) Evict(c context.Context, id string) error {
+	return q.EvictAtOnce(c, []string{id})
+}
+
+// Evict removes a pending task from the queue.
+func (q *fifo) EvictAtOnce(c context.Context, ids []string) error {
 	q.Lock()
 	defer q.Unlock()
 
-	var next *list.Element
-	for e := q.pending.Front(); e != nil; e = next {
-		next = e.Next()
-		task, ok := e.Value.(*Task)
-		if ok && task.ID == id {
-			q.pending.Remove(e)
-			return nil
+	for _, id := range ids {
+		var next *list.Element
+		for e := q.pending.Front(); e != nil; e = next {
+			next = e.Next()
+			task, ok := e.Value.(*Task)
+			if ok && task.ID == id {
+				q.pending.Remove(e)
+				return nil
+			}
 		}
 	}
 	return ErrNotFound
diff --git a/cncd/queue/queue.go b/cncd/queue/queue.go
index 67ffe3ee5..29bccb20e 100644
--- a/cncd/queue/queue.go
+++ b/cncd/queue/queue.go
@@ -123,9 +123,15 @@ type Queue interface {
 	// Error signals the task is complete with errors.
 	Error(c context.Context, id string, err error) error
 
+	// Error signals the task is complete with errors.
+	ErrorAtOnce(c context.Context, id []string, err error) error
+
 	// Evict removes a pending task from the queue.
 	Evict(c context.Context, id string) error
 
+	// Evict removes a pending task from the queue.
+	EvictAtOnce(c context.Context, id []string) error
+
 	// Wait waits until the task is complete.
 	Wait(c context.Context, id string) error
 
diff --git a/model/queue.go b/model/queue.go
index 6e5148692..d47e7a034 100644
--- a/model/queue.go
+++ b/model/queue.go
@@ -119,3 +119,14 @@ func (q *persistentQueue) Evict(c context.Context, id string) error {
 	}
 	return err
 }
+
+// Evict removes a pending task from the queue.
+func (q *persistentQueue) EvictAtOnce(c context.Context, ids []string) error {
+	err := q.Queue.EvictAtOnce(c, ids)
+	if err == nil {
+		for _, id := range ids {
+			q.store.TaskDelete(id)
+		}
+	}
+	return err
+}
diff --git a/router/router.go b/router/router.go
index 82bcaab8e..7e2125270 100644
--- a/router/router.go
+++ b/router/router.go
@@ -113,7 +113,7 @@ func Load(mux *httptreemux.ContextMux, middleware ...gin.HandlerFunc) http.Handl
 		repo.POST("/move", session.MustRepoAdmin(), server.MoveRepo)
 
 		repo.POST("/builds/:number", session.MustPush, server.PostBuild)
-		repo.DELETE("/builds/:number", session.MustRepoAdmin(), server.ZombieKill)
+		repo.DELETE("/builds/:number", session.MustPush, server.DeleteBuild)
 		repo.POST("/builds/:number/approve", session.MustPush, server.PostApproval)
 		repo.POST("/builds/:number/decline", session.MustPush, server.PostDecline)
 		repo.DELETE("/builds/:number/:job", session.MustPush, server.DeleteBuild)
diff --git a/server/build.go b/server/build.go
index a1501484d..b650dbcca 100644
--- a/server/build.go
+++ b/server/build.go
@@ -160,8 +160,6 @@ func GetProcLogs(c *gin.Context) {
 // DeleteBuild cancels a build
 func DeleteBuild(c *gin.Context) {
 	repo := session.Repo(c)
-
-	// parse the build number from the request parameter.
 	num, _ := strconv.Atoi(c.Params.ByName("number"))
 
 	build, err := store.GetBuildNumber(c, repo, num)
@@ -176,76 +174,63 @@ func DeleteBuild(c *gin.Context) {
 		return
 	}
 
-	cancelled := false
+	if build.Status != model.StatusRunning && build.Status != model.StatusPending {
+		c.String(400, "Cannot cancel a non-running or non-pending build")
+		return
+	}
+
+	// First cancel/evict procs in the queue in one go
+	procToCancel := []string{}
+	procToEvict := []string{}
 	for _, proc := range procs {
 		if proc.PPID != 0 {
 			continue
 		}
-
-		if proc.State != model.StatusRunning && proc.State != model.StatusPending {
-			continue
+		if proc.State == model.StatusRunning {
+			procToCancel = append(procToCancel, fmt.Sprint(proc.ID))
 		}
-
-		// TODO cancel child procs
-		if _, err = UpdateProcToStatusKilled(store.FromContext(c), *proc); err != nil {
-			log.Printf("error: done: cannot update proc_id %d state: %s", proc.ID, err)
+		if proc.State == model.StatusPending {
+			procToEvict = append(procToEvict, fmt.Sprint(proc.ID))
 		}
-
-		Config.Services.Queue.Error(context.Background(), fmt.Sprint(proc.ID), queue.ErrCancel)
-		cancelled = true
-	}
-
-	if !cancelled {
-		c.String(400, "Cannot cancel a non-running build")
-		return
-	}
-
-	c.String(204, "")
-}
-
-// ZombieKill kills zombie processes stuck in an infinite pending
-// or running state. This can only be invoked by administrators and
-// may have negative effects.
-func ZombieKill(c *gin.Context) {
-	repo := session.Repo(c)
-
-	// parse the build number and job sequence number from
-	// the repquest parameter.
-	num, _ := strconv.Atoi(c.Params.ByName("number"))
-
-	build, err := store.GetBuildNumber(c, repo, num)
-	if err != nil {
-		c.AbortWithError(404, err)
-		return
-	}
-
-	procs, err := store.FromContext(c).ProcList(build)
-	if err != nil {
-		c.AbortWithError(404, err)
-		return
-	}
-
-	if build.Status != model.StatusRunning {
-		c.String(400, "Cannot force cancel a non-running build")
-		return
 	}
+	Config.Services.Queue.EvictAtOnce(context.Background(), procToEvict)
+	Config.Services.Queue.ErrorAtOnce(context.Background(), procToEvict, queue.ErrCancel)
+	Config.Services.Queue.ErrorAtOnce(context.Background(), procToCancel, queue.ErrCancel)
 
+	// Then update the DB status for pending builds
+	// Running ones will be set when the agents stop on the cancel signal
 	for _, proc := range procs {
-		if proc.Running() {
-			if _, err := UpdateProcToStatusKilled(store.FromContext(c), *proc); err != nil {
-				log.Printf("error: done: cannot update proc_id %d state: %s", proc.ID, err)
+		if proc.State == model.StatusPending {
+			if proc.PPID != 0 {
+				if _, err = UpdateProcToStatusSkipped(store.FromContext(c), *proc, 0); err != nil {
+					log.Printf("error: done: cannot update proc_id %d state: %s", proc.ID, err)
+				}
+			} else {
+				if _, err = UpdateProcToStatusKilled(store.FromContext(c), *proc); err != nil {
+					log.Printf("error: done: cannot update proc_id %d state: %s", proc.ID, err)
+				}
 			}
-		} else {
-			store.FromContext(c).ProcUpdate(proc)
 		}
-		Config.Services.Queue.Error(context.Background(), fmt.Sprint(proc.ID), queue.ErrCancel)
 	}
 
-	if _, err := UpdateToStatusKilled(store.FromContext(c), *build); err != nil {
+	killedBuild, err := UpdateToStatusKilled(store.FromContext(c), *build)
+	if err != nil {
 		c.AbortWithError(500, err)
 		return
 	}
 
+	// For pending builds, we stream the UI the latest state.
+	// For running builds, the UI will be updated when the agents acknowledge the cancel
+	if build.Status == model.StatusPending {
+		procs, err = store.FromContext(c).ProcList(killedBuild)
+		if err != nil {
+			c.AbortWithError(404, err)
+			return
+		}
+		killedBuild.Procs = model.Tree(procs)
+		publishToTopic(c, killedBuild, repo, model.Cancelled)
+	}
+
 	c.String(204, "")
 }
 
@@ -353,7 +338,7 @@ func PostApproval(c *gin.Context) {
 		}
 	}()
 
-	publishToTopic(c, build, repo)
+	publishToTopic(c, build, repo, model.Enqueued)
 	queueBuild(build, repo, buildItems)
 }
 
@@ -557,7 +542,7 @@ func PostBuild(c *gin.Context) {
 	}
 	c.JSON(202, build)
 
-	publishToTopic(c, build, repo)
+	publishToTopic(c, build, repo, model.Enqueued)
 	queueBuild(build, repo, buildItems)
 }
 
diff --git a/server/hook.go b/server/hook.go
index fdbe8f8dd..eee048430 100644
--- a/server/hook.go
+++ b/server/hook.go
@@ -285,7 +285,7 @@ func PostHook(c *gin.Context) {
 		}
 	}()
 
-	publishToTopic(c, build, repo)
+	publishToTopic(c, build, repo, model.Enqueued)
 	queueBuild(build, repo, buildItems)
 }
 
@@ -360,7 +360,7 @@ func findOrPersistPipelineConfig(build *model.Build, remoteYamlConfig *remote.Fi
 }
 
 // publishes message to UI clients
-func publishToTopic(c *gin.Context, build *model.Build, repo *model.Repo) {
+func publishToTopic(c *gin.Context, build *model.Build, repo *model.Repo, event model.EventType) {
 	message := pubsub.Message{
 		Labels: map[string]string{
 			"repo":    repo.FullName,