MOSCOW (Reuters) – Several prominent Russian businessmen on Thursday called for detained U.S. investor Michael Calvey to be released from a pre-trial detention facility on bail, saying his treatment at the hands of the authorities over fraud charges looked too harsh.

The detention last month of Calvey, founder of the Baring Vostok private equity group, on embezzlement charges, which he denies, has rattled some foreign investors and politicians in Russia who are worried about the business climate.

Thursday’s calls for leniency in the case were made on the sidelines of a high profile business forum in Moscow which President Vladimir Putin attended.

Putin, who has not intervened in the Calvey case despite being lobbied on the matter by various businessmen, met some of Russia’s most influential business people on Thursday to hear their concerns.

Some of those who attended said wider concerns about the way the authorities treated businessmen accused of white collar crimes like Calvey had been aired, but that his specific case had not been mentioned.

“The circumstances of the Calvey case are not completely clear to business and that’s why it’s causing concern,” Andrey Kostin, CEO of Russia’s second-largest lender VTB and one of the people who met Putin on Thursday, said.

“I think the measures taken against Calvey (locking him up in a pre-trial detention facility) are without doubt over the top and that he could easily have been left at liberty until all the circumstances were established.”

State prosecutors have charged Calvey with fraud along with three other executives from his fund, accusing them of embezzling 2.5 billion roubles ($38.2 million).

Calvey denies the allegations, saying the case is being used to apply pressure on him in a business dispute over a Russian bank in which he is a shareholder.

Boris Titov, presidential commissioner for entrepreneurs’ rights, told reporters at Thursday’s forum that he and other business associations were working to try to get Calvey freed on bail.

“An entrepreneur should not be behind bars when his business is operational. They (Baring Vostok) have investments in more than 40 firms. We can radically change the way that the business climate in Russia is seen if he’s let out on bail.”

Businessman Grigory Berezkin, who controls ESN Group, also said Calvey’s case could have been handled more gently, suggesting he could have been put under house arrest instead.

Matthias Schepp, chairman of the board at the Russian-German Chamber of Commerce, called the Calvey case “very damaging” for Russia.

“Unfortunately we know of not just one but several instances where investment has been put off because of this.”

($1 = 65.4810 roubles)