KYIV, Jan 16 - Ukrainian police are now investigating two major cases related to the impeachment trial of President Donald Trump, one around possible illegal surveillance of former U.S. Ambassador to Ukraine Marie Yovanovitch and the other around a suspected attack by Russian military hackers targeting a company where the son of former Vice President Joe Biden sat on the board, ABC News reported.

On the Yovanovitch case, the interior ministry said in a statement Thursday that police had opened a criminal investigation in light of text messages released by Democrats on the House Intelligence Committee this week between two associates of President Donald Trump's personal lawyer Rudy Giuliani.

On the alleged hacking case, Ukrainian police said Thursday they were now investigating a suspected attack by Russian military hackers that targeted Burisma, the Ukraine-based energy company that employed Hunter Biden.

Earlier this week, cyber-security firm Area 1 said it had discovered that hackers who appeared to be from Russia's military agency, the GRU, had mounted a concerted phishing campaign against Burisma employees, trying to break into their emails and collect data.

The attacks occurred at the height of the impeachment hearings in November, and Area 1 speculated that the Russian hackers were searching for material that could be damaging to the Bidens that could then be leaked, following a model they had used in the 2016 election against the Democrat candidate Hillary Clinton.

Ukraine's cyber police said it believed the attack -- which also targeted Kvartal 95, the production company that produced President Volodymyr Zelenskiy's TV show before the former actor was elected -- was "probably committed by the Russian special services" and they were in the process of identifying the people involved. It said Ukraine had also asked the FBI to join the investigation.

Meanwhile, in the text messages released by the House committee this week, Republican congressional candidate Robert Hyde appeared to suggest to Lev Parnas, a Florida businessman now at the center of the impeachment controversy, that he had people following Ambassador Yovanovitch's movements in Ukraine.

Ukrainian police are now looking to see if there was surveillance and, if so, whether it had violated Ukrainian law or international conventions obliging host countries to protect foreign diplomats there, the ministry said.

"Ukraine's position is not to interfere in the domestic affairs of the United States of America. However, the published records contain the fact of possible violation of the legislation of Ukraine and the Vienna Convention on Diplomatic Relations, which protects the rights of a diplomat in the territory of another country," the ministry's statement said.

"After analyzing these materials, the National Police of Ukraine upon their publication started criminal proceedings under part 2 of Art. 163 (Violation of the secrecy of correspondence, telephone conversations, telegraph or other correspondence) and part 1 of Art. 182 (Unlawful collection, storage, use of confidential information about a person, violation of privacy) of the Criminal Code of Ukraine," the statement continues.

The ministry said investigators were examining whether any laws had been broken or if the messages had simply been "bravado and fake in an informal conversation between two US citizens." Ukraine's Interior Minister Arsen Avakov has requested the U.S.' assistance in the investigation, it said. (abc/ez)