The mayor of Dagestan’s largest city, who has survived 15 assassination attempts and employs a large security force to protect him, was arrested on murder charges Saturday by heavily armed forces in armored personnel carriers and helicopters, Russian officials said.

Said Amirov, the 59-year-old mayor of Makhachkala, has been in a wheelchair since 1993, when one attempt on his life severed his spine. His southern Russian city is known for frequent bombings and shootouts among police, criminal gangs and Islamic fighters. For six months last year it was home to Tamerlan Tsarnaev, one of the accused Boston Marathon bombers. His parents live there now.

Amirov was seized by troops wearing camouflage, helmets and bulletproof vests and armed with automatic rifles. They surrounded his palatial house on the Caspian Sea, according to a video shown on LifeNews, a Web site that has close connections to the security services. The streets in the neighborhood were blocked by heavy-duty machinery, and troops took cover behind a tall fence, aiming their weapons at the house. Amirov did not resist and was reportedly flown to Moscow by helicopter.

Vladimir Markin, a spokesman for the Investigative Committee, Russia’s version of the FBI, said that Amirov was arrested on suspicion of ordering the killing in December 2011 of Arsen Gadzhibekov, a detective and supervisor for the Committee in Dagestan. Ten other suspects were also arrested, including a nephew of Amirov.

LifeNews reported that officials are also investigating Amirov’s possible involvement with a criminal gang known as the Kolkhozniki (the name for Soviet-era collective farmers.) The gang allegedly includes high-ranking officials involved in drug trafficking and other criminal enterprises in Dagestan.

In Russia, one question nearly always arises when an arrest is made: Why now? The answer was unclear Saturday. President Vladimir Putin, however, recently appointed a new acting president of the Dagestan region, Ramazan Abdulatipov, amid speculation that the usual corruption has gone too far or that officials want order to be imposed on the North Caucasus before the 2014 Winter Olympics in Sochi.

Amirov, mayor of Makhachkala since 1998, also runs the local branch of the ruling United Russia Party. In a 2011 interview with The Washington Post, he was asked why he was the target of so many attacks on his life.

“There are people who try to live outside the law,” he said, “and I don’t let them do what they want.”