AUGUSTA — An Augusta man who allegedly stabbed a man outside an Augusta store, puncturing his lung, has been indicted on two felony assault charges.

Frank L. Tripp, 56, allegedly stabbed a 51-year-old Augusta man in the back in an altercation April 17 outside MD’s Market at 25 Western Ave.

Police responded to a report of a stabbing and found the victim with a roughly one inch-wide cut through his shirt and into his back. The man, struggling to breathe, was promptly treated by paramedics and taken by ambulance to MaineGeneral Medical Center, according to an affidavit filed by Chad Webster, an Augusta police officer. The affidavit said the stab injury had collapsed the man’s lung.

A woman who was with the man told police he was sitting on the side of the building when Tripp approached him, raised a large knife and stabbed the man in the back. The woman said she had never seen anything like it and described the knife as 6 inches to 8 inches long. The pair identified the alleged stabber as Tripp, who left the scene.

Police later found Tripp at the Eastside Boat Landing. When he was arrested, Webster wrote in the affidavit, Tripp “made several excited utterances of acting in self-defense and that (the alleged victim) has started it.”

Tripp later admitted to police he had been at the store and had a physical altercation with the man, the affidavit states. Tripp said the man punched him in the right side of his head and said a second altercation involved knives. He told police the man had been armed with a knife and threatened him with it, but police did not find a knife on the man who was stabbed. Police found two knives on Tripp when he was arrested.

Cameras at the store captured the incident, showing Tripp standing near the corner of the store holding a knife, and approaching the location where the man was found. He could be seen raising a large knife over his head and thrusting the knife downward, toward where the man was sitting, according to the affidavit.

Tripp was indicted by a Kennebec County grand jury, which met June 17. An indictment is not a determination of guilt but indicates enough evidence exists for a case to proceed toward trial.

Tripp was arrested and taken to Kennebec County jail, with bail set at $100,000 cash.

Both charges against Tripp are Class A felonies, punishable by up to 30 years in prison.