Last year, he tried to bring former NFL quarterback Tim Tebow to Moscow to play for his American football team. Now American businessman Mike Zaltsman sits in a crowded jail cell, accused of breaking a window.

The Boston entrepreneur is involved in a dispute over an office he rented from a Russian billionaire that culminated with his arrest in April.

The case underscores the unpredictable business environment in Russia, where thousands have ended up in jail because of disputes or raids by rivals. Even seemingly petty crimes are used to imprison people for months or years.

Although the property dispute is murky, Zaltsman's treatment is excessive by any standard, advocates say.

"The fact that he was jailed for a broken window — this is cruel and sadly typical of Russia," said Yana Yakovleva, founder of the advocacy group Business Solidarity.

Moscow police and investigators refused to comment on the case.

Zaltsman, who has dual Russian and U.S. citizenship, was accused of hooliganism — a broad charge that has been used against the feminist punk band Pussy Riot and Greenpeace environmental activists. If convicted, he could be imprisoned for up to seven years.

He denies he was delinquent on his rent, and says he has had no contact with U.S. Embassy officials. A State Department official disputed this, saying U.S. diplomats have been in contact with Zaltsman and were monitoring the case. The official spoke on condition of anonymity because he was not authorized to talk to the media.

Tensions have escalated this year between Moscow and Washington over Russia's annexation of Crimea and its perceived role in the bloody conflict in eastern Ukraine, along with a rise in anti-American sentiment.

But there has been no suggestion that this played a role in the Zaltsman case.

Zaltsman grew up in Russia before moving to Boston in 1996 at age 19 with his parents, one of many Jews to leave following the collapse of the Soviet Union. He became a U.S. citizen five years later and built a fortune in shipping and media ventures that he values at $10 million.

He returned to Russia in 2005, setting up his Black Storm football team, which last year won the Russian championship. He failed in a bid to sign Tebow, the former Denver Broncos quarterback, to his roster.

For seven months, the 37-year-old Zaltsman has been in Detention Facility No. 5. He says he shares a cell with up to 15 others, with no trial in sight. Each prisoner has just two square meters (21 square feet) of floor space, barely enough to lie down.

"Almost no sky and sun can be seen here," he said. "I'm forgetting how it looks."

Dmitry Popkov, the former coach of the Black Storm, was arrested with Zaltsman. He suffers from health problems that led to him pleading guilty in October to be treated while under house arrest.

In the property dispute, Zaltsman alleges he was persecuted by Andrei Gorodilov, a tycoon who counts London-based billionaire Roman Abramovich as a business partner and friend. Neither Gorodilov nor his representatives would comment.

Abramovich testified during a 2011 London trial that Gorodilov helped him in the creation of the oil company Sibneft in the 1990s. Abramovich later sold 75 percent of Sibneft to the Russian state firm Gazprom for $13 billion. Gorodilov briefly entered politics with Abramovich, serving as his deputy during his time as governor of the remote Chukotka region.

In 2013, a company controlled by Zaltsman signed a five-year lease on an office in an upscale Moscow neighborhoods from a businesswoman associated with Gorodilov. Within months, Zaltsman says, he was pressured to break the lease by Gorodilov, who took over as the registered owner of the property.

When talks broke down, Zaltsman says, Gorodilov sent about 30 men, some armed, to occupy the office and smash furniture. Zaltsman also alleges they stole $20,000 in office equipment.

Zaltsman says he and some friends first tried to film the intruders to generate publicity over what they saw as an attack. Then they moved to more aggressive methods.

On April 13, Zaltsman says, he and his supporters tried to scare Gorodilov's security into leaving. Zaltsman shouted that he was from the Russian police special forces and that "anyone who doesn't leave in the next 10 seconds will be shot on the spot." The occupants left, but in the confusion, Zaltsman says, one threw a chair through a window.

Zaltsman and Popkov were arrested 10 days later. Zaltsman was accused of breaking the window himself, while his associate was accused of assaulting one of the security men.

In two civil cases brought against Zaltsman, the courts sided with Gorodilov and said the eviction was legitimate, ruling Zaltsman's company had stopped paying rent and had ceased to be the legal tenant. Zaltsman insists he paid rent in compliance with the lease. Neither he nor his company was represented at some of the hearings.

Police have refused to comment while the criminal case is under investigation. They agreed only to provide the article of the criminal code under which the men are charged. It specifies they are accused of hooliganism while acting as part of a group and resisting police or security guards.

Zaltsman also is charged with failing to notify authorities that he holds dual citizenship, under a law that took effect this summer when he was already in custody.

Dionis Dedov, Zaltsman's lawyer, said his client is a victim of capricious justice.

"He believed he was merely restoring his rights as a tenant since there were no court rulings ordering him to evict," Dedov said. "Even with the charges that have been put forward, the detention for such a long period of time seems excessive."


Ellingworth reported from London. Varya Kudryavtseva in Moscow also contributed.