OTTAWA -- Justin Trudeau doubled down Wednesday on his support for a senior government official who suggested factions in the Indian government sabotaged the prime minister's trip to India last week -- despite a flat denial from India's external affairs ministry which labelled the theory "baseless and unacceptable."

And he got some back up from a leading Sikh politician in India, who alleged that Indian intelligence agencies hatched a conspiracy to ruin Trudeau's visit and brand him as a supporter of Sikh separatists.

Trudeau got little help at home, however. For the second consecutive day, opposition parties roasted him for his insistence that the official -- revealed by the Conservatives to be the prime minister's national security adviser, Daniel Jean -- is a member of the professional, non-partisan public service whose advice should be respected and believed.

They accused Trudeau of provoking a diplomatic crisis with India in a desperate bid to deflect blame for his trouble-plagued, eight-day tour of the country, which hit bottom with the revelation that a convicted attempted murderer and one-time Sikh separatist extremist had been invited to two events with the prime minister.

"There has never been a government, Liberal or Conservative, who has used a national security official to clean up an embarrassing mess that was self-inflicted by this prime minister," Conservative Leader Andrew Scheer told the House of Commons.

NDP foreign affairs critic Helene Laverdiere said Trudeau has managed to make a "botched" trip even worse by supporting the sabotage theory.

"Is the prime minister trying to create an international diplomatic crisis?" she asked.

However, NDP Leader Jagmeet Singh was somewhat less critical. While he said the Liberals must take responsibility for the guest lists at Trudeau events, Singh pointed out that he's been banned from entering India after criticizing its human rights record yet the Indian government had no problem issuing a visa to a convicted would-be assassin.

"It raises some legitimate questions," he said.

Jaspal Atwal -- a B.C. Sikh convicted of trying to kill an Indian cabinet minister in 1986 -- attended a reception in Mumbai, where he was photographed with Trudeau's wife. An invitation to a later reception in New Delhi was rescinded as soon as news broke that Atwal was on the guest list.

In a background briefing arranged by the Prime Minister's Office in the midst of the furor over the invitations, Jean suggested Atwal's presence was arranged by factions within the Indian government who want to prevent Prime Minister Narendra Modi from getting too cosy with a foreign government they believe is not committed to a united India.

An official spokesman for the Indian ministry repudiated that theory Wednesday.

"Let me categorically state that the government of India, including the security agencies, had nothing to do with the presence of Jaspal Atwal at the event hosted by the Canadian high commissioner in Mumbai or the invitation issued to him for the Canadian high commissioner's reception in New Delhi," Raveesh Kumar said in a brief statement posted on the ministry website.

"Any suggestion to the contrary is baseless and unacceptable."

But that was statement was contradicted by Manjit Singh GK, head of the Delhi unit of a Sikh political party that is allied with Modi's party.

"Sikhs could never imagine that the PM of a country which provided them opportunities of employment and growth would be treated so badly by the Indian government," he said in a statement reported by The Times of India.

According to The Times, GK agreed that Atwal had "close links" with Indian diplomatic officials and that certain people within the Indian government "were behind the episode which embarrassed the Canadian PM." He pointed out that Atwal had met various officials in government agencies during a visit to India last August, including the national spokesperson for Modi's party.

In the House of Commons, Trudeau did not back down on his support for Jean, whom he described as "a distinguished public servant who's served governments, regardless of their political stripe, for over 35 years." He said the previous Conservative government "so valued Mr. Jean's service" that it chose him to represent Canada in a speech to the United Nations.

Unlike the Conservatives, whom he accused of politicizing the public service at every opportunity, Trudeau asserted that his Liberal government respects and appreciates the work done by professional, non-partisan public servants, "particularly those in the national security and information areas."

"When they make recommendations or when they make statements to Canadians or to this government, we on this side of the House choose to believe them," he told the Commons. "On that (Conservative) side of the House, who knows?"

Scheer questioned how Trudeau can simultaneously blame rogue elements in the Indian government for Atwal's presence on the trip as well as British Columbia Liberal MP Randeep Sarai, who has taken responsibility for inviting Atwal and apologized for his lack of judgment. On Tuesday, Trudeau accepted Sarai's resignation as chair of the Liberals' B.C. caucus.

"Is the prime minister actually saying that (Sarai) has taken sole responsibility for a scheme concocted by the Indian government? ... How can they both be true?" Scheer asked.

Atwal, a one-time member of a Sikh separatist group that is banned in Canada and India as a terrorist organization, was convicted of attempting to kill Indian cabinet minister Malkiat Singh Sidhu on Vancouver Island in 1986.

He was also charged, but not convicted, in connection with a 1985 attack on Ujjal Dosanjh, a staunch opponent of the Sikh separatist movement who later became B.C. premier and a federal Liberal cabinet minister.

Liberal insiders said Sarai apologized again to his fellow MPs -- plenty of whom are privately appalled by Trudeau's handling of the trip and the subsequent fallout -- during a closed-door caucus meeting Wednesday morning. They said he's explained to some Liberals privately that he did not know about Atwal's conviction for attempted murder, although he was aware of the charge in the Dosanjh incident.

The Conservatives chose Alberta MP Jim Eglinski to lead off their questions during Wednesday's question period. Eglinski, a former RCMP officer, revealed he was one of the first police officers on the scene after Sidhu was shot in 1986.

"I helped him and his wife into the ambulance. It's a day I'll never forget," Eglinski said.

"The victims of terrorism, they have names, they have faces and they have families. To the prime minister, why would he ever meet with Jaspal Atwal?"

The Conservatives have proposed a motion, to be debated Thursday, calling on MPs to affirm that they value the contributions of Canadian Sikhs and Indo-Canadians to Canadian society, that they "condemn in the strongest terms all forms of terrorism, including Khalistani extremism and the glorification of any individuals who have committed acts of violence to advance the cause of an independent Khalistani state in India" and that they "stand with a united India."