The commission approved a schedule for meetings as it resumed its activities on Friday.
The panel plans to hear Bastys on May 3.
It also plans to look into the findings of a parliamentary probe conducted by the Seimas Committee on National Security and Defence, as well as into declassified and classified information from the State Security Department.
The impeachment commission was set up in late Match, but it suspended its activities until the Committee on National Security and Defense finished its probe.
The committee stated that Mindaugas Bastys, a member of the Social Democratic political group in the Seimas, had acted against the interests of the Lithuanian state by maintaining close and constant contacts with representatives of Russia's state nuclear energy corporation Rosatom.
The impeachment was initiated due Bastys' alleged ties to Yevgeny Kostin, who is seen as a representative of Rosatom, Piotr Voyeiko, a former KGB agent, Ernest Matskevich, a journalist of the Russian state channel RTR, Saturnas Dubininkas, who is said to be a former Kaunas mafia leader, and Vadim Pakhomov, a businessman suspected of illegal activity
The lawmaker denies all accusations.