MOSCOW — Russian investigators on Friday named the man who opened fire on the headquarters of the FSB security service in Moscow as Yevgeny Manyurov, a 39-year-old former security guard from just outside the capital.

Manyurov killed one FSB employee outright and wounded five other people outside the agency's main building, the former headquarters of the Soviet-era KGB, on Thursday evening, before he was himself shot dead.

A second FSB employee who had been seriously wounded later died from his wounds in hospital, bringing the death toll to two, excluding the gunman, investigators said Friday.

Authorities searched Manyurov's home at the rundown Soviet-era apartment block where he lived with his mother in the town of Podolsk outside Moscow and questioned his neighbors.

It remains unclear what his motive was.

Neighbors told Reuters that he was a quiet gun enthusiast who kept to himself. Manyurov was unmarried, had no children and appeared to have few friends, they said.

"He had a homely look about him, I never saw him hanging out with friends or drinking," said Natalya Fedorovna, a pensioner who lives in the same building.

Another, Vladimir Poruntsev, said: "He wasn’t very talkative, he was a little closed as a person."

Dmitry Tsaryev described Manyurov as a normal guy, who had once asked him to join him at a local shooting range, but that he had declined.

Neighbors said investigators had woken them up in the early hours of Friday morning when they searched Manyurov's flat. Police had cordoned off the building at one stage while they questioned people and checked their documents, they said.

Thursday's attack happened shortly after President Vladimir Putin's annual news conference while he was attending a Kremlin event to celebrate the work of the security services.

The FSB suspected the attack may have been planned to coincide with Putin's speech at the event, a source close to the FSB told Reuters on Thursday.

Some Muscovites laid flowers outside the FSB's headquarters on Friday and examined damage to the famous building.