NORWALK — Police say a Greenwich resident has been arrested for supplying the drugs that nearly killed a man in December.

According to an arrest warrant, a 22-year-old Norwalk man overdosed on Dec. 12 after he smoked fentanyl that he was told was Percocet, an addictive painkiller.

Based on an investigation, police said detectives determined that Matthew Roskoff, 25, of Greenwich, sold the fentanyl to the victim.

On Wednesday, Roskoff was arrested by Greenwich police and transferred to Norwalk. He was charged with second-degree assault and sale of a narcotic substance. He later posted a $100,000 bond and is expected to appear in court on Feb. 18.

This is the second time in less than a year that Roskoff has been accused of selling someone a nearly fatal batch of heroin.

In August, Roskoff was arrested after he was seen fleeing the scene of a Greenwich overdose, the warrant said.

The warrant said a witness called police when they saw Roskoff trying to “prop up” a male who was suffering an overdose. Roskoff ran from the scene when the witness told him police had been called, the warrant said.

In that case, police said they learned Roskoff sold the victim seven bags of heroin prior to the overdose. He was later arrested and charged with first-degree reckless endangerment and sale of a narcotic for the incident.

Roskoff pleaded not guilty to the charges and is next scheduled to appear in Stamford Superior Court on March 6.