Investigators have repeatedly failed to find evidence of foreign involvement in the letter attacks.

A central question to be answered is the extent of foreign involvement.

He also denied reports of foreign involvement in the war.

This is one reason there has been rampant speculation about foreign involvement in the bombings.

Interests alone have never been enough to enlist the nation in any grand foreign involvement.

There was often very little foreign involvement in the day-today running of the enterprises.

In what oil fields would the Iraqis want foreign involvement?

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

The merest chance that there might be foreign involvement is disturbing.

At the beginning of the 20th century, Haiti's political problems attracted increasing foreign involvement.