The Senate's ethics watchdog has found that Independent Senator Don Meredith breached the Red Chamber's ethics code by engaging in an inappropriate sexual relationship with a young woman that started when she was 16 years old.

The details are included in an explosive report released Thursday. Meredith, who was appointed as a Conservative senator by former prime minister Stephen Harper in 2010, denies many of the allegations levelled against him by the woman in question — who is identified by Lyse Ricard, the ethics officer, as "Ms. M" in the report — but concedes he had sexual intercourse with her on at least one occasion.

Ricard found reason to believe Meredith and Ms. M had intercourse three times, including once when the woman was 17 years old.

Meredith, 52, denies the allegation.

Ricard found that Meredith violated two sections of the code of ethics, namely that the Toronto-area senator and Pentecostal pastor did not uphold the highest standards of dignity inherent to his position, and that his actions reflect adversely on the institution of the Senate.

"Senator Meredith drew upon his weight, prestige and notability of his office, as well as his relative position of power as a much older adult, to lure or attract Ms. M, a teenager who, by virtue of her age, was necessarily vulnerable," Ricard said in her report. "He exploited Ms. M and the power imbalance between them."

Ricard said that normally a senator can suggest remedial measures to address their offending conduct, but Ricard said she did not think anything could assuage her concerns in this case. The report will now be referred to the Senate's ethics committee for review, which may recommend that the Senate as a whole take action — including the possibility of an expulsion.

Ricard referred the matter to Ottawa Police chief Charles Bordeleau in September 2015 because she believed the senator may have committed a Criminal Code offence.

Months later, in January 2016, the police ended their investigation and said they were not laying any charges, at which point Ricard resumed her inquiry.

Meredith told the ethics officer that he was "engaged in continuous prayers of repentance," professional counselling and had thoroughly read the ethics code. He also pleaded with her, in a letter sent March 4, 2017, not to publicly release details of the inappropriate relationship because of the risk of "serious emotion and other harm."

Meredith is married, and tweeted Thursday, on the day of the report's release, that he is "lucky" to have his wife, Michelle, in his life.

CBC News reached out to Meredith's office late Thursday for comment on the officer's report but did not hear back in time for publishing.

The extensive 33-page report catalogues how Meredith first met the woman at a Black History Month event at an Ottawa-area church in February 2013 and then proceeded to have a relationship of a sexual nature with her until May 2015. Meredith repeatedly told Ricard he had "no recollection of" many of their sexual encounters.

During a second interview on the matter, when presented with extensive evidence, including logs showing contact he had with the woman on his Senate-issued cellphone, Meredith conceded he had an inappropriate relationship with the woman but could not provide many further details.

That prompted the ethics officer to conclude that Toronto-area senator did not provide credible information, and was not a reliable witness. The ethics officer repeatedly referred to Meredith's cellphone records to corroborate Ms. M's testimony.

"I found Ms. M to be a credible witness. She generally had clear recollections of the interactions she had with Senator Meredith between 2013 and 2015. She was forthcoming in attempting to answer all questions put to her fully and to the best of her ability," Ricard wrote in her report.

Ms. M produced explicit text messages, screenshots of Skype and Viber conversations, as well as emails to show that Meredith encouraged her to stay in touch with him over the course of the relationship. On at least one occasion, she told the senator in an email that she loved him and mused about dating him.

Ms. M said that Meredith "continually encouraged her to be in a relationship with him … as we would call frequently and would constantly say things like she was 'special,'" The senator said it was a "gross lie."

The woman told Ricard the two had engaged in "partial" or "teaser" intercourse in December, 2014, when she was still 17, although Meredith repeatedly denied the allegation. Ricard nevertheless said she believes the intercourse took place.

Ms. M revealed to the ethics officer that she lost her virginity to Meredith shortly after she turned 18, on Feb. 16, 2015, at the Chateau Laurier Hotel in Ottawa. He also frequently masturbated while on-camera during video chats with the woman while in hotels and at his office at the GTA Faith Alliance. Meredith said he did not recall masturbating, but if he did, "it was an interaction," he told Ricard.

Ms. M said they again had sex in May 2015 at her apartment. Meredith denied that they had sex more than once, but Viber messages produced by the woman showed they were in contact on the day in question, and she sent the senator her apartment buzzer code.

Shortly after their first sexual encounter, in February 2015, Meredith wrote a letter of reference for Ms. M in support of her application for a parliamentary internship program. He also communicated with the woman's parents to discuss "business dealings," and sought to collaborate with the woman's sister on a non-profit initiative.

"Senator Meredith made promises and suggestions to Ms. M that would draw on the resources, weight and authority of his office as senator, as well as his external professional connections apart from that office, to promote, assist and advance Ms. M and members of her family," Ricard concludes.

Ricard launched her investigation at the request of Leo Housakos, then Speaker of the Senate, who believed the alleged relationship with a teen, if true, would constitute "conduct unbecoming of a senator" and would require disciplinary sanctions.

The senator was removed from the Conservative caucus immediately after the allegations came to light following a Toronto Star investigation in 2015.