Russian police say they have identified a suspect in the bombing that destroyed a passenger bus in the city of Togliatti Wednesday, killing eight people and wounding more than 50 others.

A top investigator told Russian television Thursday that police have searched the suspect's home, and recovered aluminum wires and nails similar to materials found at the blast site.

The investigator, Alexander Bastrykin, says the suspect was on the bus, but would not identify him or say whether he was among the dead. He also says the motivation for the bombing was not yet clear. Investigators are probing several theories, including that of a terrorist act, an attack by organized crime groups or the result of careless handling of explosives.

Togliatti is home to Russia's biggest carmaker, AvtoVAZ. The city has a reputation for violence by criminal gangs competing for a share of the lucrative auto industry. It is not known for terrorist attacks like those that affect the Caucasus region in southwestern Russia.

Some information for this report was provided by AFP and Reuters.