The Israeli company Black Cube has been spying on 20 Romanian officials with ties to the government, as well as on prominent business figures, Romanian reports said Thursday. On Wednesday, reports came out in Romania suggesting that four Israelis, including two former Mossad agents, Ron Weiner and David Geclowicz, were being investigated on suspicion of spying on one of the heads of Romania's National Anti-Corruption Directorate, Laura Codruta Kovesi. Weiner and Geclowicz were also arrested. Kovesi, known for her tough approach to high-level corruption, was appointed last month for a second term as Romania's chief anti-graft prosecutor. She has held the position since 2013. In 2015, her agency prosecuted 1,250 cases, with targets including a former prime minister and five former ministers. Kovesi also led a team that recently drew attention to the involvement of Israeli businesspeople in Romanian corruption schemes. The Israeli detainees are suspected of hacking the emails of people close to Kovesi, and of threatening and harassing family members and others close to her in an apparent effort to challenge her legitimacy. "There is no doubt that this is a matter of national security," the head of Romania's Anti-Terror Authority said Thursday. "It's a real threat to heads of the Romanian government when a woman in a position like this receives threats on her life. All the security apparatuses in Romania will have to improve to prevent incidents like these." According to reports in the Romanian media, Codruta Kovesi's father, Ioan Lascu, was the person who discovered that she was under surveillance. Lascu, a judge-investigator with 30 years' experience, noticed that unusual things were occurring around him and his daughter, and quickly contacted the police, who arrested the two Israelis. Romanian President Klaus Iohannes told a local newspaper on Thursday: "I'm sure that an investigation by the authorities will shed light on what took place, and I trust our authorities to do their work faithfully." The families of Weiner and Geclowicz arrived in Romania on Thursday to be with them. On Friday, Black Cube was expected to hire local lawyers. "They are good employees and we are sure they'll be released soon," a source close to both suspects said. Meanwhile former investigators for the Romanian secret police were quoted by the Romanian media voicing support for the Israelis. "There is nothing illegal in the Black Cube company's activity," a former senior officer said. Attorney Moti Tzibin, who has handled many cases of Israelis arrested in Romania, said Thursday that "Romania has become a police state; 150 politicians have been arrested in the last two years. It's a country that is in the midst of fighting the corruption that was spreading there, and some people are being hurt."