The article you link to literally says The OIG investigation found no support for Trump's claims that President Obama had ordered the wiretapping of Trump Towe

The article you link to literally says The OIG investigation found no support for Trump's claims that President Obama had ordered the wiretapping of Trump Tower. I don't always trust the press either and some sources much less than others but nothing about how the article characterized Montgomery seems either incorrect, or even exaggerated, to me. He has a history of making sensational claims and then being unable to back them up with actual evidence.