Here's the first of the tweets that started the current controversy.
There were later tweets dealing with the same claims.
There are a number of disturbing things about this tweet.
1. I doubt any prior President has gone public with such a negative message about his predecessor. He could have made his point without the bad or sick references. This show a lack of respect and a lack of class and commitment to civil discourse in a democracy. Trump has refused to apologize. Does this sound a little paranoid?
2. The information apparently came from Breitbart news and/or some conservative talk-show. No one of reasonable caution would rely on those kinds of source to make these accusations. Trump and his spokespeople have refused to make public the source of their information. It does not appear to have come from the NSA, CIA or FBI. This is immature, class and irresponsible. He easily could have checked with those agencies.
Thus far no source or confirming evidence have been found by the Senate Judiciary committee. Some Republicans in Congress have been critical of the President.
3. Now Trump is claiming, without any supporting evidence, that British Intelligence carried out the wiretapping.
4. The source for the claim against the British came for a Trump supporter at Fox and was later disavowed by Fox
"The saga began on Tuesday on “Fox & Friends,” the chummy morning show, where Mr. Napolitano made a bizarre and unsupported accusation: Citing three unnamed sources, he said that Britain’s top spy agency had wiretapped Mr. Trump on behalf of President Barack Obama during last year’s campaign.