He stated this in an interview with Welt am Sonntag.
According to him, experts with the help of two research vessels took samples of water, soil and fragments of pipelines from the scene of the incident.
The results of the analysis of the taken materials, Frank noted, do not indicate the involvement of Russia.
Nevertheless, the investigation will continue, the prosecutor general concluded.
Earlier, The Times wrote that German experts investigating gas pipeline explosions admit that they could have been carried out by one of the Western states.
On September 26, 2022, Nord Stream 2 AG announced an emergency on the Nord Stream 2 gas pipeline.