When Sinn Féin resigned last year, the party’s president defended his decision not to reveal that a senator had been suspended for sending inappropriate emails to a teenage boy.
Niall O Donghail, who is also a former mayor of Belfast, confirmed that police had been alerted but no formal complaint had been lodged.
Mary Lou MacDonald said following the introduction by Sinn Féin, there had been no finding of illegality and no criminal charges had been brought.
She has been under pressure over her party’s handling of recent child protection issues.
Mr Ó Donghail admitted in a statement to the Irish News on Tuesday that he had sent inappropriate emails to a 17-year-old boy in Northern Ireland who is a youth member of his party.
The messages are believed to have been personal in nature, but were not sexually explicit.
The party said that upon receiving the complaint in September 2023, in accordance with its child protection policy, it suspended Mr Ó Donghail and referred him to police and social services.
In the same month, Sinn Féin said the PSNI had told it it was not conducting an investigation.
Mr Ó Donghail later resigned from the party.
McDonald said on Tuesday that another adult also received inappropriate text messages from Mr Ó Donghail and was advised of his right to lodge a complaint, but did not.
In a statement to the Irish News, Mr Ó Donghail said he had accepted the actions that warranted his stepping down from his role in the Senad and as a member of the party.
He said this would give him “space to focus on improving” health and wellbeing, adding that it was an issue he had been working on since 2021.
BBC News NI has contacted him for comment.
In a statement at the time, Mr Ó Donghail said he had been unable to attend the Seanad since the summer holidays “on medical advice”.
At the time, McDonald released a statement thanking him for his contribution to the party.
During Tuesday’s debate, she reiterated that she had previously taken time off due to “serious mental health issues.”
“At the time he resigned, we were informed that he had suffered a mental health crisis following the charges and was deemed medically unfit for work,” McDonald said.
“We were concerned that publishing his name might be a risk to his health and had very serious concerns about his health and safety. I still have those concerns. I’m holding you.”
“Questions without answers”
Democratic Unionist Party (DUP) leader Gavin Robinson said in a social media post reacting to Tuesday’s news that Mr Ó Donghail’s resignation had “enabled a clean defection”, but that “they have no real I knew why.”
“The disrespect and apparent cover-up continues,” he added.
The DUP and Ulster Unionist Party have called on First Minister Michelle O’Neill to make a statement in parliament on the issue.
Tánaiste and Fianna Fáil leader Michael Martin said the recent revelations about Ó Donghail “raise serious and fundamental questions about the party and its governance”.
He claimed the Oireachtas had been “misled as to the full reasons” for his resignation.
“When it comes to Sinn Féin, it’s clear that the party will always come first,” he said.
Analysis from BBC News NI political correspondent Brendan Hughes:
These disputes may have different complexities and timelines, but they all raise issues of accountability and transparency.
Sinn Féin’s political opponents will be lining up to ask who knew what and when.
In particular, there will be a focus on how Sinn Féin has dealt with issues related to child protection.
Sinn Féin hopes McDonald’s full commitment to the party’s actions will ease the heat of recent weeks.
But political opponents on both sides of the border will argue that many questions remain unanswered.
Learn more about Brendan here.
Tuesday’s Dáil debate provided an opportunity for the parties to discuss another issue regarding Sinn Féin’s response to a separate incident involving former spokesperson Michael McMonagle, who has admitted to child sex crimes.
The party faced criticism after it emerged that two Sinn Féin spokesmen had provided references from former colleagues for jobs at charities.
In September, McMonagle admitted a series of offenses, including attempting to induce a child to engage in sexual activity.
He is scheduled to be sentenced in the coming weeks.
Press secretaries Sean Mag Widir and Caolan McGinley have since resigned.
Mr McDonald said this had instigated a review of the party’s internal procedures.
Mr MacDonald said in a newspaper on Tuesday that two former press secretaries offered job references to Michael McMonagle while he was under investigation for child sex crimes, an act that was “reprehensible and unacceptable”. I repeated that.
He said Mag Widir and McGinley “jumped before being pushed because they knew what they were doing was conduct that warranted dismissal.”
The Sinn Féin leader also apologized directly to the British Heart Foundation for “being embroiled in this controversy”.