SOUTHINGTON — A local man charged after authorities seized numerous firearms from an apartment and storage unit Tuesday first drew the attention of police when he tried to sell an AR-15 style rifle he built online, according to court documents.

Quac Hao Lam, 24, 35 Darling St., Unit Q, was charged with possession of a handgun without a permit, 29 counts of possession of a high capacity magazine, and one count of possession of an assault weapon.

On Tuesday, local police, state police, members of the Bureau of Alcohol, Tobacco and Firearms and the Central Emergency Response Team served a search warrant on Lam’s apartment in the Summer Brook complex on Darling Street.

The search warrant was based on an anonymous tip that someone was attempting to sell an assault rifle, police spokesman Lt. Stephen Elliott said. Police were notified on Sept. 12 about a listing on Armslist.com for an AR-15 style rifle with no serial number, according to Lam’s arrest warrant. Police noted the listing stated “no brand. new. has drop in trigger. No serial. Completed from 80 lower. Carbine length. No paperwork. I need money.” and was being sold for $650.

Police and a special agent from ATF contacted the seller posing as a potential buyer. Police obtained the IP address, which was registered to Lam at the Darling Street address, the warrant said. During a conversation with the buyer, Lam said he had built the weapon.

Police found videos online showing what appeared to be the same weapon. The rifle had a pistol grip and an adjustable stock, classifying it as an assault rifle by state statute.

On Tuesday, Lam was found walking in the parking lot of the apartment complex with a loaded Sig Sauer semi-automatic handgun, three fully loaded magazines for the weapon and $20,952 in cash, the warrant said. He also admitted owning six rifles in a storage unit at Public Storage on Spring Street. He took police to the unit and gave them access.

In the storage unit, police found two 12-gauge shotguns, two .22 caliber rifles, and one 7.62 mm rifle, all of which were registered to Lam. Police also found a short-barrel AR-15 type-weapon without a stock that did not have a serial number.

Police also seized assorted caliber ammunition, 11 high-capacity magazines, two boxes and two belts of shotgun shells, and four .22 caliber magazines. At Lam’s apartment, police found four assault rifles that were being built, five semi-automatic handguns, two tasers, body armor, assorted high-capacity magazines for handguns, a drill press and tools that are used to work on or build firearms, and over 1,000 rounds of ammunition, Elliott said.

There was no answer at Lam’s apartment Wednesday morning. A neighbor said she was not home during the incident on Tuesday, but received text messages from other residents about what was going on. She said neighbors reported a loud bang and many police vehicles in the area.

Police said Lam was obtaining parts of firearms and completing the manufacturing process in his apartment, the warrant said.

Lam was arraigned in Bristol Superior Court on Wednesday. The prosecutor said this was the most dangerous case he has dealt with. A public defender noted the charges were for possession, and there were no allegations that the weapons were used.

Judge John Cronin set bond at $1 million and continued the case to Dec. 6 to determine if it will be transferred to New Britain Superior Court.

“This should not happen in this day and age,” Cronin said.