Mr Krupski said he had found evidence in company data which suggested that requirements relating to the safe operation of vehicles that had a certain level of autonomous or assistive-driving technology had not been followed.
He added that even Tesla employees had spoken to him about vehicles randomly braking in response to non-existent obstacles - known as "phantom braking". This also came up in the data he obtained around customer complaints.
Mr Krupski said he had felt compelled to share what he had found with data protection authorities.
The US Department of Justice have been investigating Tesla over its claims relating to its assisted driving features since January. Tesla has also faced similar probes and questions from agencies including the National Highway Traffic Safety Administration about its autopilot system.
German newspaper Handelsblatt published the "Tesla Files" after Mr Krupski shared 100GB of internal data he discovered.
The data protection authority in the Netherlands, where Tesla's European headquarters are based, confirmed to the BBC it had been notified of the data breach and was looking into the claim.
This is the best summary I could come up with:
Lucasz Krupski leaked data, including customer complaints about Tesla's braking and self-driving software, to German newspaper Handelsblatt in May.
But, in his first UK interview, Mr Krupski told the BBC's technology editor, Zoe Kleinman, he was concerned about how AI was being used - to power Tesla's autopilot service.
Mr Krupski said he had found evidence in company data which suggested that requirements relating to the safe operation of vehicles that had a certain level of autonomous or assistive-driving technology had not been followed.
Tesla has also faced similar probes and questions from agencies including the National Highway Traffic Safety Administration about its autopilot system.
Jack Stilgoe, an associate professor at University College London who researches autonomous vehicles, said Mr Krupski's claims raised wider concerns about the technology.
The UK Government announced plans for an Automated Vehicles Bill to outline a legal framework for self-driving cars in the King's Speech in early November.
The original article contains 520 words, the summary contains 153 words. Saved 71%. I'm a bot and I'm open source!
It's interesting how AutoTLDR bot changed the spelling of his name