diff --git a/cmd/server/db.go b/cmd/server/db.go
index b366c79d..046c46d3 100644
--- a/cmd/server/db.go
+++ b/cmd/server/db.go
@@ -459,12 +459,22 @@ func (db *DB) buildTransmissionWhere(q PacketQuery) ([]string, []interface{}) {
 		args = append(args, strings.ToLower(q.Hash))
 	}
 	if q.Since != "" {
-		where = append(where, "t.first_seen > ?")
-		args = append(args, q.Since)
+		if t, err := time.Parse(time.RFC3339Nano, q.Since); err == nil {
+			where = append(where, "t.id IN (SELECT DISTINCT transmission_id FROM observations WHERE timestamp >= ?)")
+			args = append(args, t.Unix())
+		} else {
+			where = append(where, "t.first_seen > ?")
+			args = append(args, q.Since)
+		}
 	}
 	if q.Until != "" {
-		where = append(where, "t.first_seen < ?")
-		args = append(args, q.Until)
+		if t, err := time.Parse(time.RFC3339Nano, q.Until); err == nil {
+			where = append(where, "t.id IN (SELECT DISTINCT transmission_id FROM observations WHERE timestamp <= ?)")
+			args = append(args, t.Unix())
+		} else {
+			where = append(where, "t.first_seen < ?")
+			args = append(args, q.Until)
+		}
 	}
 	if q.Node != "" {
 		pk := db.resolveNodePubkey(q.Node)