PARANÁ, Argentina — An Argentine court reopened an investigation on Thursday into accusations that former President Cristina Fernández de Kirchner sought a secret deal with Iran in connection with the 1994 bombing of a Jewish center in Buenos Aires. The original case was filed by Alberto Nisman, the prosecutor whose mysterious death in 2015 convulsed the country.

Three judges on the Court of Cassation, Argentina’s highest criminal appeals court, voted unanimously to reopen the criminal complaint, which accused Mrs. Kirchner and her foreign minister, Héctor Timerman, among others, of sealing a deal with Iran to cover up the role Iranian officials were said to have played in the bombing of the Jewish community center, which killed 85 people.

An appeal to the Supreme Court by Mrs. Kirchner is possible, but legal experts say it could face challenges because the Court of Cassation did not issue a final ruling on the case, but rather called for a new investigation.

“Of course we are going to appeal,” said Alejandro Rúa, Mr. Timerman’s lawyer. “This case has been plagued with violations of constitutional guarantees. And if we run out of local instances of appeal, we are going to the Inter-American Commission of Human Rights.”