Seven Guatemalan citizens filed suit on Monday against U.S. health officials over nonconsensual medical experiments – including the infection of hundreds of Guatemalans with syphilis – carried out by U.S. doctors starting in the 1940s.

The Washington office of Fort Lauderdale, Fla.'s Conrad & Scherer and New York’s Parker Waichman Alonso are handling the class action, which was filed in U.S. District Court for the District of Columbia.

The class action stems from a 2009 study by Susan Reverby, a Wellesley College professor who found evidence that the U.S. government signed off on nonconsensual experiments on Guatemalan prisoners, orphans and patients in a mental hospital between 1946 and 1948. President Obama issued an official apology following the release of Reverby’s study.

The complaint [.pdf] filed in federal court broadens the scope of the allegations. The plaintiffs accuse U.S. officials of carrying out experiments and infecting Guatemalans with syphilis through the early 1970s.

Piper Hendricks, one of the Conrad & Scherer attorneys handling the case, said that given parallels with the experiments in Tuskegee, Ala., in which hundreds of African American men with syphilis were left untreated as U.S. doctors studied the effects of the disease from the 1930s through the 1970s, “there is no clear-cut timeline for what happened in Guatemala.”

Hendricks said her firm has previously worked on suits involving human rights issues in Latin America, so when news of Reverby’s study broke, they were contacted about pursuing a class action. She said she expects the class to grow as word spreads; the complaint notes that there were at least 700 test subjects and that thousands of people could have been affected.

An attorney with Parker Waichman Alonso could not immediately be reached today for comment.