Prosecutors said they would not punish Victor Gevers because he acted “ethically.”
It comes after Mr Gevers shared what he said were screenshots of the background of the US president’s account on October 22, during the final stages of the US election.
At the time, the White House denied it was hacked, while Twitter said it had no evidence of it.
In a statement following the latest developments, the social media firm said: “We have not seen any evidence to corroborate this claim, including in the article released in the Netherlands today.
“We have proactively implemented account security measures for a designated group of high-level election-related Twitter accounts in the United States, including federal branches of government. ”
Mr. Gevers has been discovering security vulnerabilities in software and websites for 22 years. He said he was performing a semi-regular scan of the Twitter accounts of top US candidates when he managed to guess Mr. Trump’s password.
He said he was happy not to be punished for the hacking, adding, “It’s not just my job, but all the volunteers who are looking for vulnerabilities on the internet. ”
Dutch police said: “The hacker published the login himself.
“He later told police he investigated password strength because there were vested interests at stake if that Twitter account could be taken over so soon before the presidential election. ”
They had sent their findings to US authorities, they added.
Mr Gevers had told the police that he had much more evidence of the “hack”.
In theory, he could have seen all of the president’s data, including private messages and photographs.
Earlier this year, Mr Gevers also claimed that he and other security researchers logged into Mr Trump’s Twitter account in 2016 using a password – “yourefired” – linked to another of their social media accounts during a previous data breach.