The cause of death of Chris Cornell, frontman for the iconic grunge rock band Soundgarden, is being disputed, the AP reports, with Cornell’s family disputing “inferences that Chris knowingly and intentionally” killed himself.

“The family said in a statement that without toxicology tests completed, they can’t be sure what led to his death, or if any substances were involved,” the AP reports. “According to lawyer Kirk Pasich, Cornell had a prescription for the anti-anxiety drug Ativan, which he said has various side effects.”

Cornell was found dead in his hotel room following a concert in Detroit, as we reported previously. The Wayne County Medical Examiner’s Office reportedly ruled Cornell’s death a suicide by hanging.

“Cornell’s wife, Vicky Cornell, said in the statement that when she spoke to her husband after the Detroit show, he told her he may have taken ‘an extra Ativan or two’ and was slurring his words,” the AP reports.