Former Wilco guitarist Jay Bennett's death was caused by an overdose of the painkiller Fentanyl, according to a coroner in Illinois.

Bennett, who had suffered from long-term hip pain due to a stage-diving accident, was found unresponsive in his home on May 24 earlier this year, and died later that day.

Champaign County coroner Duane Northrup said that tests showed the 45-year-old's cause of death as an overdose of fentanyl, a drug used to treat chronic pain.

The Illinois authorities are investigating the death as accidental.

Bennett left Wilco in 2001 and released several solo albums before his death.