Robert Vineberg, 57, was arraigned on felony drug charges including criminal possession of a controlled substance and criminal use of drug paraphernalia in New York City Wednesday.
While police have not linked Vineberg to Hoffman's death, investigators tell ABC News that the suspect knew the actor and even had his phone number stored in his cell phone.
A couple was also arrested on misdemeanor charges of possessing cocaine. Juliana Luchkiw was released Thursday without bail, Max Rosenblum on $35,000 bond. The 22-year-olds are due back in court later this month.
The Manhattan District Attorney's Office has reportedly declined to prosecute a fourth suspect because there was no evidence he had any control over the drugs.
Investigators zeroed in on the four alleged suspects after a tipster told police he had seen the actor at the lower Manhattan apartment building where they were arrested Tuesday. He believed that's where Hoffman got the heroin.
Luchkiw and Rosenblum had two bags of cocaine, while investigators found about 300 packets of heroin, a bag of cocaine and about $1,200 in cash in Vineberg's apartment, according to criminal complaints.
Lawyers for the three suspects denied their clients had any role in Hoffman's death.
"This case and the charges against Mr. Vineberg have absolutely nothing to do with the death of Philip Seymour Hoffman. … We're hoping the (district attorney) will not use Mr. Vineberg as a scapegoat," said his lawyer, Edward Kratt, who declined to say whether Vineberg knew Hoffman.
Hoffman was found dead of an apparent drug overdose in his Manhattan apartment Sunday. Officials say there was a needle in his arm.
Investigators found syringes, more than 70 dime bags of heroin and numerous prescription drugs in the apartment. They also discovered buprenorphine, a drug used to treat heroin addiction.
Police said Tuesday that the heroin recovered at Hoffman's apartment tested negative for the powerful additive, fentanyl. The synthetic morphine has been linked to 22 suspected overdose deaths in western Pennsylvania.
Detectives are reviewing surveillance video to try to piece together Hoffman's activities in the hours leading up to his death. Officials said the actor made six ATM transactions for a total of $1,200 inside a supermarket near his home the day before his death.
Hoffman was supposed to pick up his three children on Sunday but never showed up. When Hoffman didn't show up the next morning to pick up his kids, his friend, David Katz, and another person checked on him and found him dead.
On Wednesday, Broadway's marquee lights dimmed for a minute while mourners held a candlelight vigil outside the 90-seat home of the LAByrinth Theatre Company in tribute to the late Oscar-winning actor.
"We come together tonight in a spirit of terrible mourning and incredible loss," the Rev. Jim Martin, a Jesus priest and LAByrinth member, told the crowd of about 200 people. "But we also come together to celebrate a remarkable life."
Hoffman appeared in 50 films in less than 25 years. He was nominated for an Oscar for his performances in "The Master," "Charlie Wilson's War" and "Doubt,"and won an Oscar for his leading role in the 2005 film "Capote." He also appeared in films such as "The Big Lebowski" and "Almost Famous" and "The Hunger Games: Catching Fire," as Plutarch Heavensbee.
Hoffman is survived by his longtime girlfriend, costume designer Mimi O'Donnell, and their three young children.
A wake was held at the Frank E. Campbell Funeral home in Manhattan Thursday. A private funeral is expected to be held Friday for family and close friends. Plans are also underway for a larger memorial service later this month.
Organizers also plan to honor the late actor with a special screening of "Capote" at the annual Berlin International Film Festival Tuesday.
ABC News and The Associated Press contributed to this report.