Those who move in the Tun Dr Mahathir Mohamad circle said the former premier had been critical of various government policies for some time now.
He had told a number of those in the circle he was planning to write about it in his chedet.cc blog and that he would come down hard on Datuk Seri Najib Tun Razak.
What they did not expect was how hard it would be, to the extent of declaring that he was withdrawing support for Najib and which, in contemporary culture, might be equivalent to unfriending someone on Facebook.
Dr Mahathir is an exacting man with strong opinions and high expectations and he speaks his mind. That was exactly what he did on Monday, listing down, in point-form, his misgivings about the policies of Najib's administration as well as taking a jab at Najib's political style.
An Umno official who called on Dr Mahathir at his Petronas Twin Tower office the day the Mahathir volcano erupted had a deja vu moment. The same official had been to see Dr Mahathir at the same office back in 2006 shortly before Dr Mahathir started his attacks against the administration of Tun Abdullah Ahmad Badawi.
"It has been boiling for some time, he said he is going to write more," said the official.
Dr Mahathir, who celebrated his 89th birthday last month, is still going strong. He retired in 2003 but still keeps an eagle eye on the country's policies, especially policies that were set in place during his 22 years as prime minister or what some call his "babies".
He has been deeply unhappy about the abolition of restrictive laws like the ISA, ties with Singapore, the BR1M programme, handling of race and religious issues and Barisan Nasional's performance in the general election. He was also critical of policies like the priority on imported goods, extra holidays for workers and the hike in minimum wage all of which he said was not good for the economy.
All that, said one of his officers, is just the tip of the iceberg. Dr Mahathir is also critical of the MAS bailout, the state of Proton, the ISIS militant threat to national security and the use of foreign consultants in the government.
Is Najib about to suffer the same fate as Pak Lah?
Well, Dr Mahathir has since qualified that he is not out to oust Najib but is doing it for love of the people and country. That is good to hear because toppling two successors in a row is not a good track record.
Najib had chosen not to react to the attack. In fact, the word from his office is that he does not want any one of his supporters especially from within Umno to retaliate.
Only the top Umno figures have been authorised to comment and they are only to talk about what Najib has done. They are not to counter attack or show any disrespect to the former premier.
Najib is naturally upset that the man whom he regards as a father figure is doing this in such an open fashion but the Malay in him would not dream of hitting back at the older man. He has learnt well from the earlier episode when the inexperienced team around Pak Lah took the hardline approach against Dr Mahathir.
Dr Mahathir's attack was not exactly a bolt out of the blue for Najib.
A highly-placed source said Dr Mahathir had sent a letter to Najib shortly before the start of Ramadan to say that, "I hereby withdraw my support for you".
It is not known how Najib responded to the letter but about a week after that, Dr Mahathir attended a buka puasa event at the Prime Minister's official residence where Najib played the gracious host, solicitously spooning rice and food onto Dr Mahathir's plate.
However, Dr Mahathir was missing at the private Hari Raya do at Tan Sri Muhyiddin Yassin's house on Monday night where Najib was guest of honour.
There are two ways to remove a sitting premier - one is via a general election and the other is if his own party rejects him. Pak Lah's exit was a result of the second reason.
In that sense, Najib's position is quite secure - he won the general election and he had a successful Umno election last year where all his men won well. Umno is at its most stable in years.
Dr Mahathir cannot topple him or damage him in a direct way. But his criticism, if it increases in tempo, will give bullets to the other side, cause wear and tear, and dent Najib's image over time.
Despite the silence on the part of Umno leaders, the Umno ground is throbbing with discussion about what has happened. Many actually agree with the sentiments expressed although they may not agree with the way it was aired.
Voice of wisdom
"Some of them are saying he should speak up before it is too late. Of course, there are also people who imagine it has to do with Mukhriz (Datuk Mukhriz Mahathir) and other issues. But my take is that it is vintage Mahathir. Who else has his credibility to speak like that?" said policy analyst Dr Azmi Omar.
Tun Mahathir, said Dr Azmi, represents the voice of wisdom because of his experience.
"The PM has to take it in that light. When he did it to Pak Lah, you could feel the waves rippling through the party. It's different this time. People in the party are listening to what he says but they are with Najib," he added.
Besides, the latest economic figures favour Najib. Domestic growth for the first six months hit 6.4 per cent compared to 5.5 per cent for the same period last year, fuelled by strong export growth and private domestic demand.
Moreover, a day after Dr Mahathir opened fire, the KLSE recorded new highs with 5.1 billion shares worth an estimated RM2.9bil changing hands.
But even those who want him to continue speaking up admit that Najib is dealing with what is known as "legacy issues", inherited from the Mahathir years. For instance, they point out that one of Umno's headaches, Datuk Seri Anwar Ibrahim, was brought into the party by Dr Mahathir, groomed by him and eventually sacked by him.
Najib, for want of a better term, has been left holding many of Dr Mahathir's "babies". He has been very tactful about not blaming the past regime. His reasoning is that he is part of that government.
The Prime Minister, said a Najib insider, will continue to engage Dr Mahathir.
"He is the former PM, the decorum and respect has to be there. Najib's stand is that, we will listen and take note but we have to make decisions that are appropriate for the time and situation," said the insider.
The politics of the Mahathir era can never be replicated and there will never be another prime minister like him. He has no peers, he is in a class of his own.
Dr Mahathir also had a predecessor breathing down his neck in the early years. Tunku Abdul Rahman was a fierce critic and had used his column in The Star to voice his opinions.
But he proved Tunku and other critics wrong and went on to become, in Umno's eyes, the greatest prime minister Malaysia will ever have. Dr Mahathir was so famous for doing things his way that people used to play the Frank Sinatra song, I Did It My Way, at dinner functions where he was present.
Najib is operating in a different era. He has to tackle a new generation of voters and an unfamiliar political landscape.
He is also a totally different personality from Dr Mahathir. His peers in politics say that Najib's strength and weakness is that he is a "nice guy". He comes from an upper crust background, he went to boarding school in England and those who work with him say that he is never rude even when angry. He is basically a well brought boy who became a polished gentleman.
Najib's misfortune is that the current political landscape is dominated by loud and confrontational street-fighters. As such, the gentlemen types are bound to come across as somewhat soft and laidback.
Some still hanker for the years when there was a strong, patriarchal style leadership.
"The days of strongman politics is a thing of the past and so are the days of sweeping electoral majorities," said a Malay corporate figure.
Dr Mahathir had been firing a number of warning shots since the general election. The shots usually go off before the Umno general assembly because he wants the Umno grassroots to think about what he says and do the appropriate thing.
He resigned as Proton chairman on the eve of last year's Umno general assembly to signal his displeasure over the way the government was handling the national car industry. He was eventually persuaded to return to Proton.
Shortly after that, the Petronas executives gave him a red carpet doa selamat kenduri where everyone lined up to kiss his hand. He gave a short speech that was sprinkled with his usual wit, saying that he did not expect a busy life after retiring but he is now moving between three offices.
He has a sentimental attachment to the Petronas Twin Towers office which he said was the tallest office in South-East Asia, perhaps even Asia. He used the term "tertinggi" which, the Petronas executives noted, could also mean the "highest office" and which, of course, has its own subtle meaning.
By and large, everyone especially those in Umno have accepted the fact that Dr Mahathir will be Dr Mahathir. No one can stop him from speaking out and, truth be told, some people do want him to do that.
An opinionated Mahathir is something that Najib has to live with. The concern of those around the Prime Minister is whether Dr Mahathir will take it to another level.
But for as long as it is sincere and fatherly criticism, Najib will take it and continue to engage Umno's grand old man.