MOSCOW — A 30-year-old Russian man suffering depression after a breakup went on a shooting spree Wednesday in his Moscow office, killing five and wounding another two after declaring his hatred for mankind, investigators said.

Dmitry Vinogradov, 30, posted an online manifesto in which he proclaimed his "hatred for humankind as a species" hours before the killing spree, prompting comparisons with Norwegian killer Anders Behring Breivik.

"I hate human society and being part of it disgusts me! I hate the meaninglessness of human life!" Vinogradov wrote in a manifesto posted on one of Russia's top social networks, VKontakte.

"I hate the life itself. I see only one way to justify it: to eliminate as many particles of human compost as possible."

Vinogradov opened fire at the offices of the pharmacy chain Rigla in northeast Moscow Wednesday morning, killing two women and three men and gravely injuring another woman and man, the Investigative Committee said. website, known for its close ties to law enforcement agencies, cited Vinogradov's mother Yelena as saying the young man was depressed over a breakup with his girlfriend who worked with him.

"On the morning of November 7, 2012, the suspect came into the office of the pharmaceutical company he works for and fired numerous shots from Saiga and Benelli shotguns that he owns," the statement said.

"Two men and two young women sitting at their desks died on the spot," it said, adding Vinogradov killed another man at the stairs leading to the offices.

"One more man and another young woman were seriously wounded, they are receiving medical help," the Investigative Committee said, adding that the company's security guards had detained him.

A spokeswoman for the Investigative Committee, told AFP the man had shot from two guns simultaneously. He was placed under arrest and is being questioned by investigators.

Most of his victims are believed to be his colleagues.

The Interfax news agency, citing a representative of the Investigative Committee, said Vinogradov's former girlfriend was "safe and sound," adding she would be questioned.

Yelena Vinogradova told her son had in January broken up with his girlfriend who she called Anya. He worked at the drugs company's legal department and she in the financial department, his mother said.

"He bought her a trip to Edinburgh, booked everything, paid for everything, and two days before (the trip) he said: 'I am not going anywhere.'"

"Then he began suffering from an awful depression," the 56-year-old woman said, adding her son was also taking medication prescribed by a doctor.

Vinogradova said after breaking up with his girlfriend he had bought a rifle and had gone to firing ranges outside Moscow to practice shooting.

The state RIA Novosti news agency, citing a law enforcement source, said earlier in the day the attacker was suffering from unrequited love.

"He told investigators that he had fallen in love with a girl who was a pharmacist, but his feelings were not reciprocated."

"Because of that he drank for five days and today he came in and opened fire."

The Investigative Committee spokeswoman declined to comment about possible motives for the killings.

The Interfax news agency said, citing a law enforcement source, said Vinogradov would have to undergo a psychological evaluation,

"He is of course not Breivik but the analogy suggests itself," the source was quoted as saying.

By 1400 GMT, Vinogradov's VKontakte page showed more than 1,100 "likes" for his manifesto.

Breivik, a 33-year-old right-wing extremist from Norway, was in August found sane by an Oslo court and sentenced to his country's maximum sentence of 21 years for July 2011 bombing and shooting frenzy that left 77 people dead.

[Man with gun via Shutterstock]