Former 3 Doors Down guitarist Matt Roberts died at the hands of a physician who was negligent and a pharmacy that enabled the doctor ... so claims Matt's estate in a new lawsuit.
The estate named Dr. Richard Snellgrove and Rite Aid as the ones responsible for Matt's death ... this according to new legal docs obtained by TMZ.
The estate claims Snellgrove's the one who prescribed high levels of opioids and benzodiazepines to Matt for years prior to his death. The suit claims Snellgrove has already been indicted in Alabama for Matt's death. The estate also faults Rite Aid for failing to comply with the Controlled Substances Act.
TMZ broke the story ... Matt died of an apparent overdose. He was scheduled to perform at a charity event when he was found dead in his hotel room. Matt's dad believed the possible OD was accidental.