Horror at what appeared to be a narrowly averted attempt on the life of a former president has been giving way to widening skepticism, as Argentinians start to nurse doubts that Vice President Cristina Fernandez de-Kirchner’s life was ever in real jeopardy and accuse her of using the event for political ends. 

Shortly after the purported assassination attempt on Thursday, President Fernandez declared a national holiday. The affair further deepened Argentina’s political divisions. Mrs. Kirchner’s supporters are intensifying protests in her defense, while opponents mounted counter-protests. 

Mrs. Kirchner is using the affair to “hunt for symbolic enemies,” a former president and a member of an opposition party to Mrs. Kirchner, Mauricio Macri, said in a statement posted on social media. He accused the ruling party of using the botched attack for political gain.

A 35-year old Brazilian national, Fernando André Sabag Montiel, was arrested Thursday, accused of approaching Mrs. Kirchner near her home, armed with a pistol. A widely distributed video showed him pressing the gun to her cheek. The pistol misfired, according to the government. 

Skeptics note that in the immediate investigation following the incident, Mrs. Kirchner said she didn’t even notice the assassin and casually went on to sign autographs. Additionally, investigators were unable to crack open Mr. Montiel’s cellphone and after transferring it to a different team, the phone was reformatted, erasing all data. 

A former CIA agent, Guillermo Cueto, told a popular broadcast outlet, Radio Mitre, that the bullet that was to be used for the attack, a .32 caliber bersa, has less than 0.01 percent failure rate. “I think he wasn’t there to murder someone but to fake a murder,” Mr. Cueto opined.

Hashtags like #IDontBelieveThem and #WeAreNotStupid trended on Argentinian social media immediately following the event. “It was #AllStaged. Can we go to work now?” Argentinian print and television journalist Jorge Lanata, who has exposed past corruption of members of the Kirchner family, tweeted Friday morning after Mr. Fernandez declared a national holiday. 

“Raise your hand if you think that this show was created by the Kirchners,” a La Nacion journalist, Carlos Pagni, one of the first to raise doubts on the case, wrote in a Twitter thread. He then enumerated numerous past affairs that met with public skepticism, including the 2015 assanination of a Kirchner critic, prosecutor Alberto Nisman. Mrs. Kirchner insists the murder of the prosecutor was a suicide. 

“They lied with Nisman, they lied with Maldonado, they said that they did not know Lázaro Báez, they said that the bags belonged to Macri, they lied with the plane with terrorists, they stole the vaccines. Why aren’t they going to lie about this?” Mr. Pagni tweeted. 

Minutes after 9 p.m. Thursday, Mrs. Kirchner was greeting supporters waiting outside her house in the upscale neighborhood of Recoleta, when Mr. Montiel appeared to have attempted to shoot her and his pistol failed to discharge.

A few hours later, President Fernandez called the attempt “the most serious incident since we reinstituted democracy” in 1983, when Argentina’s military dictatorship ended. He then declared Friday a national holiday and called on the public to “express themselves in defense of life, of democracy and solidarity with our vice president.”

The attack “deserves the most energetic repudiation from the whole of Argentine society, from all political sectors, and all the men and women of the republic, because these events affect our democracy,” Mr. Fernandez said. 

Some Argentines spent all day Friday marching in front of the presidential palace, known as Casa Rosada, at the historic Plaza de Mayo. Others went to work, ignoring the government-imposed federal holiday that they considered an excuse to instigate violent protest on behalf of Mrs. Kirchner.

The governors of Mendoza and Jujuy provinces declined to enforce the national holiday.  

The president of Mr. Macri’s opposition consetvative party, Juntos por el Cambio, Patricia Bullrich, tweeted: “The president is playing with fire: Instead of seriously investigating a serious incident, he points fingers at the opposition and the press, decrees a holiday to mobilize his militant supporters, and turns an individual act of violence into a political event. Regrettable.”

The Fernandez-Kirchner government has been in free fall for some time. Inflation in Argentina reached 7 percent in August, and economists predict it could soon reach a three-digit annual inflation rate. 

Even more pointedly, Mrs. Kirchner is on trial for corruption and is facing a potential sentence of 12 years in prison. She is accused of leading a scheme that transferred funds from the state coffers to a friend of the Kirchners, Lazaro Baez, in the form of public contracts. 

Mr. Fernandez accused the prosecutor, Diego Luciani, of sputtering “endless legal nonsense,” and expressed the hope that he “doesn’t do the same” as the late prosecutor. “Nisman killed himself,” Mr. Fernandez said. “I hope prosecutor Luciani doesn’t do the same.”

This generated anger among Argentines and international figures, as it was seen as a warning against Mr. Luciani. The opposition right-wing party announced it would initiate legal action against the president for “instigation of suicide and threat of mafia murder against Prosecutor Luciani.”