Moscow [Russia], July 12: A former Russian submarine captain who worked as a mobilisation officer has been shot dead while jogging in the southern Russian city of Krasnodar.
Several Russian media outlets speculated that Stanislav Rzhitsky, 42, may have been tracked via his profile on the Strava fitness app.
Russian investigators say they arrested a man in connection with the killing.
The suspect was named Serhiy Denysenko, born in the Ukrainian city of Sumy in 1959.
Several Russian Telegram channels claimed Mr Denysenko was the former head of the Ukrainian Karate Federation.
The Investigations Committee has also released a video of the alleged arrest, but the man's face is blurred in it, making it difficult to verify the identity of the person.
It later published CCTV footage allegedly of Capt Rzhitsky on his morning run, followed by a man on a bike.
The former naval officer was shot in the back and the chest in a park near the Olimp sports centre, the Russian daily newspaper Kommersant reported.
Baza, a Russian Telegram channel with close ties to the police, reported that the killer could have tracked Capt Rzhitsky's runs on Strava as he regularly followed the same route while running.
A BBC Verify analysis of Capt Rzhitsky's profile - which is public - shows that he frequently ran through the area where he is reported to have been killed.
A facial analysis carried out by the BBC confirmed the profile belonged to Capt Rzhitsky.
His address and personal details had also been uploaded to the Ukrainian website Myrotvorets (Peacemaker), a vast unofficial database of people considered to be enemies of Ukraine.
The word "liquidated", in red letters, has now been superimposed on his photograph on the site.
In a statement, Ukraine's military intelligence said the park was deserted due to heavy rain, "so there are no witnesses who could provide details or identify the attacker".
Anton Gerashchenko, a Ukrainian interior ministry adviser, tweeted that Russian media were accusing Ukraine of involvement but he did not say whether that suspicion was justified.
Capt Rzhitsky's watch and headphones were found at the scene, indicating robbery was not the motive, according to Russian news outlet Mash.
He reportedly commanded the Krasnodar submarine, named after the city, in the Russian navy.
Ukrainian media has said he could have been in command of the vessel when it carried out a missile attack on the Ukrainian city of Vinnytsia in July 2022, which killed 28 people, including three children.
The Ukrainian government said the attack came from Kalibr cruise missiles launched from a submarine in the Black Sea.
But Baza has quoted Capt Rzhitsky's father saying that his son resigned from the Russian armed forces in December 2021 - before Russia's full-scale invasion of Ukraine.
He subsequently became the deputy mobilisation officer in the Krasnodar region.
Source: Fijian Broadcasting Cooperation