A Border Patrol agent is being investigated for possibly starting the Sawmill Fire currently burning in southern Arizona.

Tucson Sector Border Control said in an email to 12 News that one of its agents was "involved in recreational shooting" while off-duty and "immediately reported the fire after it begun [sic]."

The fire, which started Sunday, has burned upwards of 40,000 acres as of Thursday. It is 20 percent contained, according to fire officials.

RELATED: Winds causing concern about Sawmill Fire

Border Patrol did not identify the agent and referred all further questions to the state fire agency.

Windy conditions Thursday have some officials concerned about the possibility of the fire spreading.