Polish prosecutors said Monday they have again summoned EU President Donald Tusk to testify as a witness in Warsaw regarding the 2010 presidential jet crash in Russia that killed Poland's then president and 95 others.
The former liberal Polish prime minister was summoned for July 5 to testify regarding "public officials who failed to comply with obligations" concerning crash victim autopsies, Ewa Bialik, a spokeswoman for national prosecutors, told the Polish news agency PAP.
Tusk already testified for eight hours in the Polish capital last month as a witness in an investigation of two former military counter-intelligence chiefs accused of overstepping their duties.
An arch-rival of Jaroslaw Kaczynski -- the powerful leader of the conservative governing Law and Justice (PiS) party -- Tusk said at the time that "this whole affair is extremely politically motivated."
He was first summoned days after EU leaders gave him another term as president despite strong opposition from Poland.
Kaczynski's late twin brother and then president, Lech Kaczynski, died in the 2010 crash in Smolensk, Russia that also killed a number of senior Polish statesmen.
Jaroslaw Kaczynski has long insisted that the 2010 crash was no accident and even accused Tusk, who was prime minister at the time, of "moral responsibility" for the death of his brother.
Polish and Russian investigators had found that pilot error, bad weather and poor air-traffic control were to blame for the crash.
But the PiS launched a fresh probe and a commission of enquiry suggested last month that an explosion likely caused the aircraft to break up in the air.
The crash occurred as the presidential delegation was heading to a ceremony in Russia's Katyn forest for thousands of Polish army officers killed by Soviet secret police in 1940 -- a massacre the Kremlin denied until 1990.