Vygivsky attached a photo of the arrest, showing a shirtless man being apprehended by officers in military uniform in what appeared to be an apartment.
He said the killer had checked to make sure Parubiy was dead before he fled the scene. Ukraine’s national broadcaster said the perpetrator had used an electric bicycle.
The interior minister earlier said the killing had been carefully planned, echoing President Volodymyr Zelenskyy.
Zelenskyy said Interior Minister Igor Klymenko and security service chief Vasyl Maliuk had informed him of the arrest.
In a subsequent post after having spoken to chief prosecutor Ruslan Kravchenko, he added: “The suspect has given an initial testimony.”
Klymenko said dozens of police officers and security officers had been involved in the arrest in the Khmelnytsky region of western Ukraine.
“I will only say that the crime was carefully prepared: the schedule of the deceased’s movements was studied, the route was laid, and an escape plan was thought out.”
Law enforcement sources cited by the Ukrainian branch of media outlet RFE/RL said the arrested suspect told investigators he had made contact with Russian agents when he was seeking information on his son, missing on the front line in 2023.
Ukraine’s interior ministry, queried on this by AFP, refused to confirm or deny that report.
Wanted by Russia
Some earlier tributes from Ukrainian officials to Parubiy, who was still a member of Parliament, hinted at Russian involvement.
Since Russia’s invasion of Ukraine began in 2022, both sides have accused each other of assassinations of key political and military figures.
Russian state media said Parubiy has been wanted by Russian authorities since 2023.
Parubiy, who had studied history, had campaigned for Ukraine’s independence from the Soviet Union.
He was also a major supporter of the use of the Ukrainian language over Russian.
During the Maidan protests of 2014, he was a “commander” of opposition self-defence forces.
The demonstrations led to the ouster of Ukraine’s pro-Kremlin leadership and precipitated a Moscow-backed separatist uprising in the east of the country.
That same year, Ukrainian media said he survived an assassination attempt by grenade.
After the ousting of then-Ukrainian leader Viktor Yanukovych, who fled to Russia, Parubiy served on the National Security and Defence Council for several months.
-Agence France-Presse