Ukraine’s Security Service (SBU) has detained two Chinese citizens in Kyiv on suspicion of attempting to steal classified documentation related to the RK-360MC Neptune missile system.

According to a report published by the SBU on Telegram, one of the suspects is a 24-year-old former student at a Kyiv technical university who, reportedly stayed in Ukraine after being expelled in 2023 due to academic underperformance.

The second individual is the student’s father, who lives in China but occasionally visited Ukraine to coordinate his son’s alleged intelligence activities.

The investigation found that the younger suspect aimed to obtain technical documentation on the production of Ukraine’s Neptune missile system by recruiting a Ukrainian citizen working on advanced weapons being developed for Ukraine’s Defense Forces.

“The SBU’s counterintelligence exposed the spy at the early stages of his activity and detained him red-handed while he was transferring classified documents,” the report states. “His father, who was responsible for relaying the material to the Chinese intelligence services, was also detained.”

Both suspects have been charged under Part 1 of Article 114 of Ukraine’s Criminal Code – espionage. If convicted, they face up to 15 years in prison.

In late June, SBU reported the detention of a traitor within the Armed Forces of Ukraine (AFU) who was allegedly helping Russia plan a strike on the Neptune anti-ship missile system guarding part of the Black Sea.

According to the SBU, the suspect is a 33-year-old serviceman assigned to a unit protecting Neptune missile systems. He had been recruited by Russia’s military intelligence (GRU) after posting pro-Kremlin content on social media.

The GRU handler instructed him to collect and send geolocated data on Neptune launch sites and nearby training centers, including ones where he had previously trained. This intelligence would be used to guide Russian cruise missile and kamikaze drone strikes. In return, he was promised advance notice of the attacks so he could escape to a “safe area.”

An SBU source said this case was part of a broader Russian effort to “hunt down” Ukraine’s Neptunes and other missile platforms.

The R-360 Neptune is a modernized version of the Soviet Kh-35 anti-ship cruise missile, developed by Kyiv’s Luch Design Bureau and adopted by Ukraine in 2020. The Neptune has a range of up to 300 kilometers (190 miles) and used to strike both naval and ground targets.

Two Neptunes are said to have been used to sink the cruiser Moskva, the flagship of Russia’s Black Sea Fleet in April 2022. After being hit, the ship caught fire, suffered internal explosions, and eventually capsized and sank during a storm with other Russian vessels unable to assist.

The Moskva was one of the largest warships in the Black Sea and among the six largest in the entire Russian Navy. According to Forbes, the estimated value of the destroyed vessel was around $750 million.

Since the full-scale invasion in 2022, Ukraine has reportedly developed new Neptune variants with land-attack capabilities and extended ranges of up to 1,000 kilometers (625 miles).