(CNN) -- Prosecutors in Hungary indicted a Nazi war crimes suspect Tuesday with involvement in the brutal treatment and deportation of thousands of Jews during World War II.
Ladislaus Csizsik-Csatary was allegedly "actively involved" in sending nearly 12,000 Jews to various concentration camps in the spring of 1944, according to the Metropolitan Chief Prosecution Office in Budapest.
According to prosecutors, Csizsik-Csatary served as a senior Hungarian police officer in the city of Kosice, which is now in Slovakia but was under Hungarian rule in the 1940s.
Csizsik-Csatary topped the Simon Wiesenthal Center's list of "most wanted Nazi war criminals" as of April this year.
The Wiesenthal Center, a worldwide Jewish rights organization, and a British tabloid, The Sun, highlighted the case against him last year after the suspect, who is reportedly in his late 90s, was found living in Hungary in 2011.
The prosecution's indictment describes how most of the local Jewish people were forced into a ghetto and a deportation camp housed in a brick factory in April 1944, a month after the town was occupied by German troops.
Csizsik-Csatary was made commander of the "collection and deportation camp" in the brick factory at the beginning of May 1944, it says.
During that month, he "regularly beat the interned Jews with his bare hands and whipped them with a dog-whip without any special reasons and irrespective of the sex, age or health condition of the assaulted people," the indictment alleges.
From mid-May to the start of June, the almost 12,000 Jews held in the camp were transported in packed freight wagons to the concentration camps in German-occupied territories. The majority of the Jews deported from Kosice went to Auschwitz, it says.
The defendant "was actively involved in and assisted the deportations," the indictment says.
In early June, he also allegedly "prohibited cutting windows on the wagons which could have helped the about 80 people being crammed under inhuman circumstances in the windowless wagons to get more fresh air."
The indictment concludes that Csizsik-Csatary "intentionally assisted the unlawful executions and tortures committed against Jewish people who were deported."
According to the Wiesenthal Center, Csizsik-Csatary was previously convicted in absentia and sentenced to death for torturing Jews and his role in the mass deportation to Auschwitz.
He escaped to Canada after World War II but was stripped of his Canadian citizenship in 1997, and chose voluntarily to leave the country, the center claims.
He was rediscovered in the fall of 2011 as part of the center's Last Chance project, and was charged last July with the torture of Jews in the Kosice ghetto, it says.
In March this year, a Slovak court commuted his death sentence to life imprisonment to enable Slovakia to seek Csizsik-Csatary's extradition from Hungary to stand trial for his crimes in Kosice, it adds.
Journalist Fanny Facsar and CNN's Marilia Brocchetto contributed to this report.