diff --git a/db.go b/db.go
index 03335c710..ae05157e9 100644
--- a/db.go
+++ b/db.go
@@ -120,7 +120,7 @@ type DB struct {
 	donec    chan struct{}
 	stopc    chan struct{}
 
-	// compMtx is used to control compactions and deletions.
+	// cmtx is used to control compactions and deletions.
 	cmtx sync.Mutex
 }
 
@@ -671,17 +671,14 @@ func (db *DB) Delete(mint, maxt int64, ms ...labels.Matcher) error {
 	db.cmtx.Lock()
 	defer db.cmtx.Unlock()
 
-	db.headmtx.RLock()
+	db.mtx.RLock()
 	blocks := db.blocksForInterval(mint, maxt)
-	db.headmtx.RUnlock()
+	db.mtx.RUnlock()
 
 	var g errgroup.Group
 
 	for _, b := range blocks {
-		f := func() error {
-			return b.Delete(mint, maxt, ms...)
-		}
-		g.Go(f)
+		g.Go(func() error { return b.Delete(mint, maxt, ms...) })
 	}
 
 	if err := g.Wait(); err != nil {
@@ -705,10 +702,7 @@ func (db *DB) appendable() (r []headBlock) {
 
 func intervalOverlap(amin, amax, bmin, bmax int64) bool {
 	// Checks Overlap: http://stackoverflow.com/questions/3269434/
-	if amin <= bmax && bmin <= amax {
-		return true
-	}
-	return false
+	return amin <= bmax && bmin <= amax
 }
 
 func intervalContains(min, max, t int64) bool {
diff --git a/db_test.go b/db_test.go
index 1fa4d7270..e410dfceb 100644
--- a/db_test.go
+++ b/db_test.go
@@ -15,6 +15,7 @@ package tsdb
 
 import (
 	"io/ioutil"
+	"math/rand"
 	"os"
 	"testing"
 
@@ -141,3 +142,77 @@ func TestDBAppenderAddRef(t *testing.T) {
 	err = app2.AddFast(string(refb), 1, 1)
 	require.EqualError(t, errors.Cause(err), ErrNotFound.Error())
 }
+
+func TestDeleteSimple(t *testing.T) {
+	numSamples := int64(10)
+
+	tmpdir, _ := ioutil.TempDir("", "test")
+	defer os.RemoveAll(tmpdir)
+
+	db, err := Open(tmpdir, nil, nil, nil)
+	require.NoError(t, err)
+	app := db.Appender()
+
+	smpls := make([]float64, numSamples)
+	for i := int64(0); i < numSamples; i++ {
+		smpls[i] = rand.Float64()
+		app.Add(labels.Labels{{"a", "b"}}, i, smpls[i])
+	}
+
+	require.NoError(t, app.Commit())
+	cases := []struct {
+		intervals intervals
+		remaint   []int64
+	}{
+		{
+			intervals: intervals{{1, 3}, {4, 7}},
+			remaint:   []int64{0, 8, 9},
+		},
+	}
+
+Outer:
+	for _, c := range cases {
+		// TODO(gouthamve): Reset the tombstones somehow.
+		// Delete the ranges.
+		for _, r := range c.intervals {
+			require.NoError(t, db.Delete(r.mint, r.maxt, labels.NewEqualMatcher("a", "b")))
+		}
+
+		// Compare the result.
+		q := db.Querier(0, numSamples)
+		res := q.Select(labels.NewEqualMatcher("a", "b"))
+
+		expSamples := make([]sample, 0, len(c.remaint))
+		for _, ts := range c.remaint {
+			expSamples = append(expSamples, sample{ts, smpls[ts]})
+		}
+
+		expss := newListSeriesSet([]Series{
+			newSeries(map[string]string{"a": "b"}, expSamples),
+		})
+
+		if len(expSamples) == 0 {
+			require.False(t, res.Next())
+			continue
+		}
+
+		for {
+			eok, rok := expss.Next(), res.Next()
+			require.Equal(t, eok, rok, "next")
+
+			if !eok {
+				continue Outer
+			}
+			sexp := expss.At()
+			sres := res.At()
+
+			require.Equal(t, sexp.Labels(), sres.Labels(), "labels")
+
+			smplExp, errExp := expandSeriesIterator(sexp.Iterator())
+			smplRes, errRes := expandSeriesIterator(sres.Iterator())
+
+			require.Equal(t, errExp, errRes, "samples error")
+			require.Equal(t, smplExp, smplRes, "samples")
+		}
+	}
+}
diff --git a/head.go b/head.go
index 8c2cf4905..72aa67a6d 100644
--- a/head.go
+++ b/head.go
@@ -153,8 +153,7 @@ func (h *HeadBlock) init() error {
 	deletesFunc := func(stones []stone) error {
 		for _, s := range stones {
 			for _, itv := range s.intervals {
-				// TODO(gouthamve): Recheck.
-				h.tombstones.stones[s.ref].add(itv)
+				h.tombstones.stones[s.ref] = h.tombstones.stones[s.ref].add(itv)
 			}
 		}
 
diff --git a/head_test.go b/head_test.go
index 07fbe377e..0463d8430 100644
--- a/head_test.go
+++ b/head_test.go
@@ -382,7 +382,7 @@ func TestHeadBlock_e2e(t *testing.T) {
 	return
 }
 
-func TestDeleteSimple(t *testing.T) {
+func TestHBDeleteSimple(t *testing.T) {
 	numSamples := int64(10)
 
 	dir, _ := ioutil.TempDir("", "test")
@@ -427,7 +427,6 @@ func TestDeleteSimple(t *testing.T) {
 Outer:
 	for _, c := range cases {
 		// Reset the tombstones.
-		writeTombstoneFile(hb.dir, newEmptyTombstoneReader())
 		hb.tombstones = newEmptyTombstoneReader()
 
 		// Delete the ranges.
diff --git a/wal.go b/wal.go
index 6de9f73ad..0e503e7b8 100644
--- a/wal.go
+++ b/wal.go
@@ -49,13 +49,13 @@ const (
 	WALEntryDeletes WALEntryType = 4
 )
 
-// SamplesCB yolo.
+// SamplesCB is the callback after reading samples.
 type SamplesCB func([]RefSample) error
 
-// SeriesCB yolo.
+// SeriesCB is the callback after reading series.
 type SeriesCB func([]labels.Labels) error
 
-// DeletesCB yolo.
+// DeletesCB is the callback after reading deletes.
 type DeletesCB func([]stone) error
 
 // SegmentWAL is a write ahead log for series data.