CAMDEN, Maine — Three people were arrested Thursday night after a search of a Union Street home police suspect is a center for heroin dealing.

Joseph Zak, 30, was charged with aggravated trafficking in heroin, trafficking in heroin, possession of oxycodone, and possession of Suboxone. The aggravated trafficking charge is because the house is located within 1,000 feet of a school — the Children’s House Montessori School, according to a police affidavit filed in Rockland District Court.

The affidavit quotes Zak’s girlfriend as telling police, after she was taken into custody at his house, that Zak had been selling heroin on almost a daily basis from the Union Street residence.

Zak told officers that he had obtained the heroin from Portland but would not identify the supplier, according to the affidavit.

The Maine Drug Enforcement Agency, Camden police and Maine State Police searched Zak’s home Thursday afternoon and early evening.

A search warrant was obtained by MDEA after an investigation in which a confidential informant reporedly purchased heroin from Zak in the area on two occasions, according to the affidavit. During the investigation, agents and officers found that Zak allegedly was meeting heroin buyers on Union Street near his residence. He would meet with two or three different cars at a time, police said.

Agents and officers executed the warrant when Zak returned to Camden after allegedly buying the heroin in Portland. Shortly after Zak returned, home agents reportedly saw him dealing to people on Union Street. Zak was approached by officers after one of the transactions and was taken into custody.

Agents also arrested Kevin Defeo, 24, of Camden for possession of oxycodone. Defeo was found to be parked on Union Street, allegedly conducting a transaction with Zak. At the time of Defeo’s arrest, a 4-year-old child was in the back seat of the car. The child was turned over to the mother, who was not involved.

Defeo told police that he was paying a debt to Zak by giving him oxycodone.

Agents reportedly seized about 3 grams of unpackaged heroin.

A gram of heroin makes about 50 bags. A bag of heroin sells for about $25-$30 in Camden.

Agents also found about 10 bags of heroin, 3 ounces of marijuana, Suboxone strips, and about 20 oxycodone tablets. None of the prescription medication seized was prescribed to Zak, according to police. Agents also seized pre-made bags for the heroin, scales and drug paraphernalia.

Cheyenne Cesarini-Yelverton, 22, of Rockland also was arrested at the residence for violation of bail. Cesarini-Yelverton was on bail out of Rockland for a previous MDEA arrest on heroin trafficking charges. She was also on bail for a Cumberland County charge of possessing heroin. A hypodermic needle and spoon were found in her purse, according to the affidavit.

Cesarini-Yelverton told police that she had come from a court hearing that day on the heroin possession charge in Portland, where she had agreed to a deferred disposition and a Maine Pretrial Services contract.

She tested positive for cocaine and opiates when tested at the jail.

All three were taken to Knox County Jail. They made their initial court appearances Friday afternoon in Rockland District Court. Judge Susan Sparaco set bail at $7,500 cash for Zak and $500 cash for Defeo. Sparaco ordered Cesarini-Yelverton held without bail and the state filed a motion to revoke her previous bail.