New York (CNN) -- Four people believed to be connected to the drugs found in Philip Seymour Hoffman's apartment were arrested late Tuesday night, law enforcement officials told CNN.
During the raid that led to the arrest of the three men and one woman, police recovered 350 small plastic bags of what is believed to be heroin, the officials said. The bags of alleged heroin were branded "black list" and "red bull" -- not the same brands found in Hoffman's apartment, the sources said.
Apartments at 302 Mott Street in Manhattan, where the four were arrested, are part of the investigation into Hoffman's death, according to a police source.
The source identified the suspects being investigated in connection with drugs sold to Hoffman as Juliana Luchkiw, 22; Max Rosenblum, 22; Robert Vineberg, 57; and Thomas Cushman, 48.
Luchkiw and Rosenblum were charged with criminal possession of a controlled substance in the seventh degree, misdemeanors, while Vineberg was charged with criminal possession of a controlled substance in the third degree, a felony.
Through their attorneys, all three entered pleas of not guilty Wednesday.
The Manhattan District Attorney's Office declined to prosecute Cushman because there was no evidence he had any control over the drugs.
Vineberg was found to have the actor's phone number stored in his cell phone, a law enforcement official told CNN. Police discovered the largest amount of what is believed to be heroin in his apartment, the source said.
Vineberg was described by a former neighbor as a talented musician who used the stage name Robert Aaron and once toured with Wyclef Jean. Vineberg had a wife and daughter, said the neighbor, who lived in the building a number of years ago.
"He used to practice at night," said the former neighbor, recounting that Vineberg played keyboards. "Honestly, he seemed like a nice guy, always playing music. Nothing sinister."
Vineberg's attorney, Edward Kratt, said that he hopes prosecutors will not use his client as a scapegoat.
"These charges have absolutely nothing to do with Philip Seymour Hoffman's unfortunate death," Kratt said.
Luchkiw's attorney, Stephan Turano, similarly said she had no connection to Hoffman, other than seeing his movies, and that Luchkiw was simply in the "wrong place at (the) wrong time."
A spokeswoman for the New York medical examiner's office said Wednesday that a determination of the cause and manner of Hoffman's death is pending further study, including toxicology reports.
When police were called to Hoffman's fourth-floor Manhattan apartment Sunday, they found the actor lying on the bathroom floor with a syringe in his left arm. He was wearing shorts and a T-shirt, his eyeglasses still resting on his head, according to law enforcement sources familiar with the inquiry.
Investigators discovered close to 50 envelopes of what they believed was heroin in the apartment, the law enforcement sources said. They also found used syringes, prescription drugs and empty plastic bags of a type commonly used to hold drugs, the sources said.
Also found in Hoffman's apartment was his personal journal, resting on a living room TV stand, two law enforcement sources said.
No fentanyl found
Preliminary tests Tuesday showed the heroin recovered from Hoffman's apartment did not contain fentanyl, a law enforcement official told CNN. More testing will be done.
Fentanyl is a powerful narcotic used to treat cancer patients' pain.
Last week, Maryland officials said heroin tainted with fentanyl had claimed at least 37 lives since September. And last month, at least 22 people in western Pennsylvania died after using heroin mixed with fentanyl.
While results of an autopsy will definitively reveal exactly how Hoffman, 46, died, the role that heroin may or may not have played is a key part of the investigation.
Police are trying to piece together the actor's movements last weekend as they look for anyone who might be linked to the drugs that apparently killed him.
On Tuesday, a law enforcement source told CNN that the night before Hoffman died, he withdrew $1,200 from a grocery store ATM near his apartment.
Hoffman got the money in six transactions Saturday night, according to the source.
A witness told investigators he saw the Oscar-winning actor talking to two men wearing messenger bags about 8 p.m.
Police are also reviewing surveillance video, including video of a restaurant where Hoffman had brunch Saturday morning with two people.
'I'm a heroin addict'
In a 2011 interview with "60 Minutes," Hoffman discussed his past struggles with drug and alcohol addiction.
"Anything I could get my hands on, I liked it all," he said.
Fear, Hoffman said, made him sober up.
"You get panicked. ... I was 22 and I got panicked for my life. It really was, it was just that," he said. "And I always think, 'God, I have so much empathy for these young actors that are 19 and all of a sudden are beautiful and famous and rich.' I'm like, 'Oh my God. I'd be dead.'"
But last year, Hoffman said he'd fallen off the wagon, started taking prescription pills and slipped into snorting heroin, according to TMZ.
Magazine writer John Arundel said he met the actor at the Sundance Film Festival in Utah two weeks before his death.
"I said, 'What do you do?' And at that point, he took off his hat and he said, 'I'm a heroin addict,'" Arundel said.
"Didn't look like he was (joking). Seemed like he was having one of those 'coming to God' moments -- where it just struck him as, 'this is the revelatory moment.'"
But actor George Clooney said he had dinner with Hoffman a few months ago, and he seemed fine.
"I have to say he seemed in pretty good shape," Clooney said. "I mean, there's no way to explain it."
Filmmaker Chris Barrett interviewed Hoffman January 17 at the Sundance Film Festival. "He didn't look well at Sundance. His skin color was very pale, but he wasn't disheveled as some media was reporting," Barrett told CNN.
Dimming the lights
Family and close friends of the actor will hold a private funeral service in New York. Plans are also under way for a memorial service later this month. No information on the dates was available.
On Wednesday night, the famed Broadway theater district will dim its marquees for one minute at 7:45 p.m. in Hoffman's memory.
He appeared on Broadway three times.
Hoffman stayed active on stage even as his star rose in Hollywood. He starred in a Broadway production of "Death of a Salesman" in 2012 and was co-artistic director of the Labyrinth Theater Company in New York.
That company hosted a candlelight vigil Wednesday night.
"I just was really profoundly affected by his death and felt like it was important for me to be here," said Leslie Kritzer, a fellow actor. "I also just think it's important to be here to remind people to have compassion and love for people that are struggling with the disease of addiction."
Kritzer said she had long admired Hoffman from afar.
"He could do the movies, and he did them brilliantly -- better than anyone else -- but he always came back to his roots and he was a hero for all of us that could only dream of doing what he accomplished," she said.
CNN's Jason Carroll, Brian Vitagliano and Adam Reiss contributed to this report.