If their investigation proved fruitless, they were to be allowed to return to California.

They'd tried to get her out, but the attempts had proven fruitless.

There were contacts in 1972 and 1975, which proved fruitless.

Efforts in earlier years to raise money from the City had proved fruitless.

Because Andrew didn't know any effort he made would prove fruitless.

Talks were held with the Government over the weekend, but they proved fruitless.

But this effort proved fruitless after the college professor died of a heart attack a few days later.

But when the search proved fruitless, the district decided to tell the students.

Efforts to work through these concerns in 1940 and 1941 proved fruitless.

I agree with you that the period of reflection is likely to prove fruitless.