Melissa Etheridge was arrested this summer for possession of marijuana at the U.S.-Canadian border.

TMZ reported this weekend that Etheridge was arrested back in August for possession of a controlled substance after her tour bus was stopped by the U.S. Customs and Border Patrol in North Dakota on the way back into the U.S. A K-9 unit detected possible drugs, according to the site, and officers later found marijuana oil.

Etheridge, who is a breast cancer survivor and who has said she uses the oil for symptoms of pain, pleaded not guilty to possession.

A rep for the singer was not immediately available to comment further to HuffPost.

The Grammy-winner has been open about using cannabis to cope with the side effects of chemotherapy.

It was a wake-up call for me, Etheridge told Yahoo in April . When I used [marijuana] as medicine, it became so clear to me that it has been maligned and misunderstood, and I really wanted to help people who are suffering. I mean, going through chemotherapy is suffering and cannabis helps so many parts of just that. Thats just the beginning of what it does medicinally.

She has also been open about smoking pot with her adult children, and pushed back against those who might judge her for it.