Fresh allegations about former finance secretary Derek Mackay suggest “the emergence of a pattern of behaviour”, political opponents have said.
Mackay, 42, was forced to resign on Thursday morning – just hours before delivering the budget – after it emerged he sent hundreds of messages to a 16-year-old boy.
A second man has since told the Daily Record that Mackay sent him inappropriate messages over a four-year period.
The Scottish Conservatives said it showed a “pattern of behaviour” and called on the SNP leadership to establish a “complete picture”.
The Scottish Sun revealed father-of-two Mackay, who came out as gay in 2013, contacted the 16-year-old via Facebook and Instagram over a six-month period and offered to take him to a rugby game and out to dinner.
In one message, he asked the boy: “And our chats are between us?”
When the youngster agreed, Mackay told him: “Cool, then to be honest I think you are really cute.”
Announcing his resignation, Mackay said: “I take full responsibility for my actions. I have behaved foolishly and I am truly sorry.”
First Minister Nicola Sturgeon later told the Scottish Parliament the Renfrewshire North and West MSP had been suspended from both the SNP and the party’s parliamentary group at Holyrood pending further investigation.
She branded his actions “unacceptable” and said they fell “seriously below the standard required of a minister”.
When questioned by Scottish Conservatives leader Jackson Carlaw, the First Minister said she was unaware of any other potential cases.
However on Friday, the Daily Record reported that Mackay sent dozens of unwanted messages to an SNP activist over a period of four years.
The Herald also claimed the First Minister had banned Mackay from drinking during conferences due to “concerns over his behaviour”.
In response, the Scottish Conservatives branded it a “grooming scandal” and said the SNP government had “huge questions” to answer.
Carlaw said: “Nicola Sturgeon, when asked yesterday in the Scottish Parliament if she had sought assurances from Derek Mackay that the story reported was an isolated incident, replied merely that she was unaware of any other potential victims.
“It is now clear that no such assurances were sought from Mr Mackay by the First Minister, given there are other people coming forward with allegations arising from his previous and additional role as SNP business convener.
“It is also now being reported that he was banned from drinking at party conferences which again suggests knowledge of potentially inappropriate behaviour.”
Carlaw accused the SNP of “protecting its own reputation” over the welfare of those messaged by Mackay.
He added: “A pattern of behaviour is now beginning to emerge, and it’s vital the SNP leadership – instead of spinning – acts to establish a complete picture.
“The Scottish Government and the SNP should have already established a confidential hotline for potential victims to contact to report concerns and to receive appropriate support.
“This is action the Scottish Parliament took without delay in response to a previous incident.
“There has been a collective failure of leadership both from the First Minister Nicola Sturgeon and the current SNP business convener Kirsten Oswald. Both now need to respond and act with far greater urgency and understanding.”
An SNP spokesman said: “Once the First Minister became aware of the allegations Wednesday evening, decisive action was taken and Derek Mackay resigned.
“He was suspended from the SNP as soon as the full details, which we had asked for the previous evening, were published by The Sun on Thursday morning.
“The SNP has established procedures for individuals to raise concerns about members, including the option of doing that independently and anonymously if they wish.”