A Sanford man was arrested Thursday and charged with three counts of aggravated trafficking in heroin, authorities said.

Brian Vance, 27, was taken into custody about 4 p.m. by officers from the Maine Drug Enforcement Agency and Sanford Police Department who have been investigating heroin distribution in Sanford.

Officers had made undercover purchases of heroin from Vance, who was arrested on Winter Street in Sanford, the law enforcement agencies said in a joint news release. After a search, he was found to be in possession of about 10 grams of a heroin-fentanyl mix with an estimated street value of $1,500, a loaded handgun and a boot knife.

Vance was charged with three counts of Class A aggravated trafficking in Schedule W drugs (heroin/fentanyl). He had been sought on arrest warrants charging two counts of trafficking in heroin.

He was taken to the York County Jail in Alfred and charged in connection with the arrest warrants, with bail set at $50,000 cash.

An additional charge of Class A aggravated trafficking in heroin while armed with a firearm was added in connection with the seizure of the heroin and firearm. Bail on that charge was set at an additional $50,000.

The investigation is continuing and other associates of Vance have been identified and additional arrests are expected, police said.