MOSCOW—A prominent Russian cybersecurity executive was arrested on suspicion of treason in a case that follows a recent spate of arrests on charges of attacking state authority and that some business leaders said risks rattling the country’s IT sector.

Moscow’s Lefortovo district court said on Wednesday that Ilya Sachkov, chief executive of Group-IB, which investigates and prevents cybercrime, would be held in detention for two months, following his arrest on Tuesday.

Anastasiya...

MOSCOW—A prominent Russian cybersecurity executive was arrested on suspicion of treason in a case that follows a recent spate of arrests on charges of attacking state authority and that some business leaders said risks rattling the country’s IT sector.

Moscow’s Lefortovo district court said on Wednesday that Ilya Sachkov, chief executive of Group-IB, which investigates and prevents cybercrime, would be held in detention for two months, following his arrest on Tuesday.

Anastasiya Romanova, a spokeswoman for the court, confirmed that Mr. Sachkov was ordered to remain in custody until Nov. 27, but said she wasn’t permitted to provide details about the charges and circumstances of the case. Details about treason cases in Russia, which can fetch a prison sentence of up to 20 years, are typically classified.

Mr. Sachkov’s legal representatives couldn’t immediately be reached for comment. Group-IB said in a statement that it was examining the court’s statement but was “confident in the innocence of the company’s CEO and his business integrity.”

The company confirmed that law-enforcement authorities had searched its Moscow office on Tuesday, but the reason for the search wasn’t clear, it said.

Based in Singapore, Group-IB bills itself as “one of the leading providers of solutions dedicated to detecting and preventing cyberattacks, identifying online fraud, investigation of high-tech crimes and intellectual property protection.”

The 35-year-old Mr. Sachkov, who founded the company in 2003, is well known in Russia’s business and IT sectors. In 2019, he was among the winners of a prestigious national award for representatives of small and medium-size businesses who met with Russian President Vladimir Putin. The Kremlin leader spoke with the awardees about how they came up with their projects and what they planned to do next, according to details published by the Russian state news agency TASS.

Over the years, Mr. Sachkov managed to attract private investors to Group-IB. The company has offices in Amsterdam, Dubai, Kuala Lumpur and Hanoi, and its products are used in more than 60 countries, according to its website. It is recommended by the Organization for Security and Cooperation in Europe, according to a May 2013 statement from the international intergovernmental organization, which said the company had “received credible information about new types of cyber threats.”

Boris Titov, Russia’s business ombudsman, called on the investigating authorities to clarify the details of Mr. Sachkov’s case or risk negative repercussions from the IT community.

“Given the scale and uniqueness of the figure of the entrepreneur Sachkov for the entire IT industry of Russia, it is necessary to explain the investigation,” Mr. Titov said in a statement. “Otherwise, the sector and its investment attractiveness will be dealt a critical blow. IT will run out of the country.”

Kremlin spokesman Dmitry Peskov told reporters Wednesday that he wasn’t worried that the case would affect the business-investment climate since “the accusations are not related to the economy, but are related to treason.”

Mr. Sachkov’s arrest on charges of attacking state authority is the latest in a series of treason cases brought by Russian authorities in recent years, including against academics, officials and at least eight scientists. Many are accused of passing sensitive material to other countries, in charges that some political observers and lawyers say highlight the government’s insecurity and mistrust as it seeks to ensure Mr. Putin’s complete control, they said.

“What we see now is just an outbreak of criminal cases on state treason,” said Ivan Pavlov, a lawyer representing Ivan Safronov, a former defense reporter working at the country’s space agency who was charged with treason last year for allegedly passing secret information to the North Atlantic Treaty Organization at the behest of the U.S.

Mr. Pavlov said that official statistics from Russia’s Justice Ministry show that up until 2014, no more than three sentences were passed a year under the articles for treason and espionage. Since then, around 15 sentences have been passed each year, he said.

Group-IB said that the company’s co-founder Dmitry Volkov would assume leadership of the firm in the near future and that all of its divisions would continue to operate as usual.

“The decentralized infrastructure of Group-IB allows us to keep our customers’ data safe, maintain business operations and work without interruption across our offices in Russia and around the world,” the company said.

Write to Ann M. Simmons at ann.simmons@wsj.com