Sinn Féin’s decision not to reveal that a senator had been suspended for sending inappropriate texts to a teenage boy when he stepped down last year has been defended by the party’s president.

Niall Ó Donnghaile, who was also a former Belfast lord mayor, confirmed police were notified but no formal complaint was received.

Mary Lou McDonald said, following a referral by Sinn Féin, there were no findings of illegality and no criminal charges were pursued.

She has come under pressure over the party’s handing of recent child safeguarding issues.

Mr Ó Donnghaile confirmed in a statement to the Irish News on Tuesday that he sent an inappropriate text to a youth member of the party, a 17-year-old boy in Northern Ireland.

The message is believed to have been personal in nature but not sexually explicit.

The party said when it got the complaint in September 2023, it followed its child protection policy, suspended the person who sent the message, and referred them to police and the social services.

The same month, Sinn Féin said the PSNI told them it was not carrying out an investigation.

Mr Ó Donnghaile later resigned from the party.

On Tuesday, McDonald said an adult had also received inappropriate texts from Mr Ó Donnghaile and was advised of their right to make a complaint but they did not.

In his statement to the Irish News, Mr Ó Donnghaile said he accepted his behaviour warranted stepping down from his role in the Seanad and as a party member.

He said it would give him “the space to focus on improving” his health and well-being, issues he added he had been dealing with since 2021.

BBC News NI has contacted him for comment.

In a statement at the time, Mr Ó Donnghaile said he had been unable to attend the Seanad since the summer recess “on the advice of my doctor”.

McDonald also issued a statement wishing him well and thanking him for his service to the party.

During a debate on Tuesday, she repeated that he had previously been on leave due to “serious mental health issues”.

“We were advised at the time he stepped down he was suffering from a mental health crisis after the complaint and was deemed medically unfit for work,” McDonald said.

“We were worried publicly naming him would be dangerous to his health and we had very serious concerns for his health and safety – I still hold some to this day.”

In a social media post reacting to the news on Tuesday, Democratic Unionist Party (DUP) leader Gavin Robinson said when Mr Ó Donnghaile stepped down his party “enabled a graceful departure” but “they knew the real reason”.

“The contempt and apparent cover up continues,” he added.

The DUP and Ulster Unionist Party have called for First Minister Michelle O’Neill to give a statement to the assembly on the issue.

Tánaiste (Irish deputy PM) and Fianna Fáil leader Micheál Martin said the latest revelations about Mr Ó Donnghaile “raise serious and fundamental questions about the party and its governance”.

He claimed the Oireachtas was “misled on the full reasons” for his resignation.

“It is apparent when it comes to Sinn Féin, the party always comes first,” he said.

As the saying goes, if you’re explaining, you’re losing.

For Sinn Féin, the best part of the past three weeks – when this controversy first began – must have felt like that.

Now it has taken a further turn with one of its former rising stars in Belfast embroiled in a different element of this, which has the potential for more political fallout.

McDonald sought to lay out a full timeline of actions the party had taken after the first complaint was made against Mr Ó Donnghaile.

And she insisted concerns for his mental health – and legal advice sought by the party – meant the party did not reveal what prompted his departure from politics last December, save for what were cited as health reasons.

There was no criminality, but for its critics the political charge against Sinn Féin remains questions of transparency.

On both sides of the border, political opponents are lining up to seek further explanations from the party.

The Dáil debate on Tuesday offered parties an opportunity to debate another issue relating to Sinn Féin’s handling of a separate case involving former press officer Michael McMonagle, who admitted child sex offences.

The party faced criticism after it emerged that two Sinn Féin press officers gave references for their former colleague for a job with a charity.

In September, McMonagle admitted to a series of offences, including attempting to incite a child to engage in sexual activity.

He is due to be sentenced in the coming weeks.

Both press officers, Seán Mag Uidhir and Caolán McGinley, have since resigned.

On this, McDonald said she has instigated an overhaul of procedures in the party.

Speaking in the Dáil on Tuesday, McDonald also reiterated that the move by two former press officers to provide Michael McMonagle with job references when he was under investigation for child sex offences was “reprehensible and unforgivable”.

She said Mag Uidhir and McGinley “knew their actions were sackable offences so they jumped before they were pushed”.

The Sinn Féin leader also apologised directly to the British Heart Foundation for “being dragged into this controversy”.