MOSCOW, January 29 (RIA Novosti) – Police suspect a 32-year-old native of the Pskov Region, believed to have targeted retirees in a killing spree more than seven years ago, of being involved in 13 murders, the Interior Ministry said in a statement on Tuesday.

The man has confessed his role in the killings, but police do not yet have enough firm evidence to confirm his guilt in the crimes, Igor Mezinov, a spokesman for the Interior Ministry's main criminal investigation unit, told RIA Novosti.

"There is enough of a basis to believe" the man is guilty of all 13 murders, Mezinov added.

Police suspect the man, currently serving an eight-year prison sentence for robbery, committed the murders in the Rostov and Pskov Regions between September and December 2005.

The suspect “entered elderly people’s homes, offering to buy an iron, a tea kettle, or something else,” the ministry said in a statement. “Upon entering the apartment, he quickly assessed the situation, after which he made the decision to kill the person.”

As a rule, the victims were poor, single pensioners over 70 years-old, police added.

Officials are also looking into whether the man may have been involved in other similar murders in Russia in 2004 and 2005.