We have to find out what pushed them to commit such a terrible crime

Colonel Nikolai Shecherbakov

The two paratroopers killed their first victims - a policemen and two civilians - as they fired at a roadblock from a car they had stolen.

Another motorist was later killed as they hijacked his vehicle.

The two servicemen have been identified as Almaz Shageyev and Mikhail Sukhorukov.

"We have to find out what pushed them to commit such a terrible crime," said Colonel Nikolai Shecherbakov, part of a committee investigating the incident.

Some say one of the boys received a letter from his girlfriend telling him she was getting married to someone else

Tartarstan Interior Ministry

One theory is that a failed relationship sparked the rampage.

"Some say one of the boys received a letter from his girlfriend telling him she was getting married to someone else," said a spokesman for Tartarstan Interior Ministry.

"But officially, we do not know what their motive was."

Bullying, poor pay and poor conditions combine to create a miserable existance for many young conscripts in Russia's armed forces - although the elite paratroops are generally seen as better off than most.

One campaign group, Soldiers' Mothers, says as many as 40,000 conscripts a year become conscientious objectors or deserters, 3,500 die each year from beatings, malnutrition and disease, and around 500 soldiers commit suicide.