Pitt voluntarily tests for drug amid child abuse investigation

"The DCFS [Department of Community & Family Services] wouldn't compel someone to provide the urine sample for the drug test; it would be voluntary," a legal source has told Us magazine.

TMZ also reported that Pitt, 52, had offered to take a drug test shortly after the jet plane incident to prove that he had nothing to hide. A second source has confirmed this.

The FBI is currently gathering evidence to evaluate whether to investigate Pitt on a federal level. It was reported that Pitt misbehaved with his kids on a private flight.

Pitt "has cooperated [with the investigation]. He certainly wants what's best for his kids and for them to be in the best environment, and he'll do anything that will put them in the best position," a source said.

Jolie, 41, filed for divorce on Monday, September 19. The former couple has six children.