diff --git a/cmd/segment-reaper/detect.go b/cmd/segment-reaper/detect.go
index ecab48dbc..b897c8fae 100644
--- a/cmd/segment-reaper/detect.go
+++ b/cmd/segment-reaper/detect.go
@@ -4,15 +4,25 @@
 package main
 
 import (
+	"context"
+	"encoding/csv"
+	"os"
+	"strconv"
+
+	"github.com/gogo/protobuf/proto"
 	"github.com/spf13/cobra"
 	"github.com/zeebo/errs"
 	"go.uber.org/zap"
 
 	"storj.io/storj/pkg/cfgstruct"
+	"storj.io/storj/pkg/pb"
 	"storj.io/storj/pkg/process"
+	"storj.io/storj/pkg/storj"
 	"storj.io/storj/satellite/metainfo"
 )
 
+const maxNumOfSegments = byte(64)
+
 var (
 	detectCmd = &cobra.Command{
 		Use:   "detect",
@@ -25,9 +35,125 @@ var (
 		DatabaseURL string `help:"the database connection string to use" default:"postgres://"`
 		From        string `help:"begin of date range for detecting zombie segments" default:""`
 		To          string `help:"end of date range for detecting zombie segments" default:""`
+		File        string `help:"location of file with report" default:"detect_result.csv"`
 	}
 )
 
+// Cluster key for objects map.
+type Cluster struct {
+	projectID string
+	bucket    string
+}
+
+// Object represents object with segments.
+type Object struct {
+	// TODO verify if we have more than 64 segments for object in network
+	segments uint64
+
+	expectedNumberOfSegments byte
+
+	hasLastSegment bool
+	// if skip is true then segments from this object shouldn't be treated as zombie segments
+	// and printed out, e.g. when one of segments is out of specified date rage
+	skip bool
+}
+
+// ObjectsMap map that keeps objects representation.
+type ObjectsMap map[Cluster]map[storj.Path]*Object
+
+// Observer metainfo.Loop observer for zombie reaper.
+type Observer struct {
+	db      metainfo.PointerDB
+	objects ObjectsMap
+	writer  *csv.Writer
+
+	lastProjectID string
+
+	inlineSegments     int
+	lastInlineSegments int
+	remoteSegments     int
+}
+
+// RemoteSegment processes a segment to collect data needed to detect zombie segment.
+func (observer *Observer) RemoteSegment(ctx context.Context, path metainfo.ScopedPath, pointer *pb.Pointer) (err error) {
+	return observer.processSegment(ctx, path, pointer)
+}
+
+// InlineSegment processes a segment to collect data needed to detect zombie segment.
+func (observer *Observer) InlineSegment(ctx context.Context, path metainfo.ScopedPath, pointer *pb.Pointer) (err error) {
+	return observer.processSegment(ctx, path, pointer)
+}
+
+// Object not used in this implementation.
+func (observer *Observer) Object(ctx context.Context, path metainfo.ScopedPath, pointer *pb.Pointer) (err error) {
+	return nil
+}
+
+func (observer *Observer) processSegment(ctx context.Context, path metainfo.ScopedPath, pointer *pb.Pointer) error {
+	cluster := Cluster{
+		projectID: path.ProjectIDString,
+		bucket:    path.BucketName,
+	}
+
+	if observer.lastProjectID != "" && observer.lastProjectID != cluster.projectID {
+		err := analyzeProject(ctx, observer.db, observer.objects, observer.writer)
+		if err != nil {
+			return err
+		}
+
+		// cleanup map to free memory
+		observer.objects = make(ObjectsMap)
+	}
+
+	isLastSegment := path.Segment == "l"
+	object := findOrCreate(cluster, path.EncryptedObjectPath, observer.objects)
+	if isLastSegment {
+		object.hasLastSegment = true
+
+		streamMeta := pb.StreamMeta{}
+		err := proto.Unmarshal(pointer.Metadata, &streamMeta)
+		if err != nil {
+			return errs.New("unexpected error unmarshalling pointer metadata %s", err)
+		}
+
+		if streamMeta.NumberOfSegments > 0 {
+			if streamMeta.NumberOfSegments > int64(maxNumOfSegments) {
+				object.skip = true
+				zap.S().Warn("unsupported number of segments", zap.Int64("index", streamMeta.NumberOfSegments))
+			}
+			object.expectedNumberOfSegments = byte(streamMeta.NumberOfSegments)
+		}
+	} else {
+		segmentIndex, err := strconv.Atoi(path.Segment[1:])
+		if err != nil {
+			return err
+		}
+		if segmentIndex >= int(maxNumOfSegments) {
+			object.skip = true
+			zap.S().Warn("unsupported segment index", zap.Int("index", segmentIndex))
+		}
+
+		if object.segments&(1<<uint64(segmentIndex)) != 0 {
+			// TODO make path displayable
+			return errs.New("fatal error this segment is duplicated: %s", path.Raw)
+		}
+
+		object.segments |= 1 << uint64(segmentIndex)
+	}
+
+	// collect number of pointers for report
+	if pointer.Type == pb.Pointer_INLINE {
+		observer.inlineSegments++
+		if isLastSegment {
+			observer.lastInlineSegments++
+		}
+	} else {
+		observer.remoteSegments++
+	}
+	observer.lastProjectID = cluster.projectID
+	return nil
+}
+
 func init() {
 	rootCmd.AddCommand(detectCmd)
 
@@ -36,6 +162,8 @@ func init() {
 }
 
 func cmdDetect(cmd *cobra.Command, args []string) (err error) {
+	ctx, _ := process.Ctx(cmd)
+
 	log := zap.L()
 	db, err := metainfo.NewStore(log.Named("pointerdb"), detectCfg.DatabaseURL)
 	if err != nil {
@@ -44,5 +172,66 @@ func cmdDetect(cmd *cobra.Command, args []string) (err error) {
 	defer func() {
 		err = errs.Combine(err, db.Close())
 	}()
+
+	file, err := os.Create(detectCfg.File)
+	if err != nil {
+		return errs.New("error creating result file: %+v", err)
+	}
+	defer func() {
+		err = errs.Combine(err, file.Close())
+	}()
+
+	writer := csv.NewWriter(file)
+	defer func() {
+		writer.Flush()
+		err = errs.Combine(err, writer.Error())
+	}()
+
+	headers := []string{
+		"ProjectID",
+		"SegmentIndex",
+		"Bucket",
+		"EncodedEncryptedPath",
+		"CreationDate",
+	}
+	err = writer.Write(headers)
+	if err != nil {
+		return err
+	}
+
+	observer := &Observer{
+		objects: make(ObjectsMap),
+		db:      db,
+		writer:  writer,
+	}
+	err = metainfo.IterateDatabase(ctx, db, observer)
+	if err != nil {
+		return err
+	}
+
+	log.Info("number of inline segments", zap.Int("segments", observer.inlineSegments))
+	log.Info("number of last inline segments", zap.Int("segments", observer.lastInlineSegments))
+	log.Info("number of remote segments", zap.Int("segments", observer.remoteSegments))
 	return nil
 }
+
+func analyzeProject(ctx context.Context, db metainfo.PointerDB, objectsMap ObjectsMap, csvWriter *csv.Writer) error {
+	// TODO this part will be implemented in next PR
+	return nil
+}
+
+func findOrCreate(cluster Cluster, path string, objects ObjectsMap) *Object {
+	objectsMap, ok := objects[cluster]
+	if !ok {
+		objectsMap = make(map[storj.Path]*Object)
+		objects[cluster] = objectsMap
+	}
+
+	object, ok := objectsMap[path]
+	if !ok {
+		object = &Object{}
+		objectsMap[path] = object
+	}
+
+	return object
+}