The nature of the crimes, particularly the last one, suggests professional terrorist involvement.

Putin suggested also equal involvement of interested European countries in the project.

She also suggested involvement of Russian special services in the alleged fabrication.

"They simply become part of the criminal fraternity, and the intelligence we have suggests deep involvement in serious and sophisticated crime activities here."

There is no direct evidence, but some scientists suggest involvement of energy from respiration.

There is no credible information to suggest foreign involvement at this point.

He didn't need to add that any fragments or discarded hand grenades discovered by police wouldn't suggest American involvement in their use.

Most service proposals suggest involvement of high school or older youth.

Several other conspiracy theories have suggested Israeli or Jewish involvement.