Over seven months after Matthew Perry's passing, investigation into part of his death remains ongoing. 

While the Los Angeles Police Department shared in January it would no longer be looking into the details of the Friends alum's October death—which was determined to be caused by "the acute effects of ketamine"—the department confirmed to E! News there is still an open investigation. 

Investigators are reportedly looking into where Perry received the ketamine that ultimately contributed to his death, specifically who provided the drug and under what circumstances, per TMZ. The outlet also reports, citing law enforcement sources, that both local police and the Drug Enforcement Administration are investigating the matter and have "already interviewed some key people in Hollywood." 

In an autopsy report obtained by E! News in December, the coroner said "high levels" of ketamine were found in his blood. The document noted that the "main lethal effects" from the medication would be cardiovascular overstimulation and slowed breathing. According to a separate LAPD press release that same month, contributing factors to Perry's passing were listed as drowning, coronary artery disease and the effects of buprenorphine, a drug commonly used to treat opioid use disorder.

According to the autopsy report, Perry had taken a ketamine infusion therapy—used to treat depression and anxiety—over a week before his Oct. 28 death. However, there were trace amounts of the medication found in his stomach when he died. The autopsy noted these trace amounts "could not be from that infusion therapy, since ketamine's half-life is 3 to 4 hours, or less." 

Additionally, the report confirmed there was no evidence of alcohol, methamphetamine, cocaine, heroin, PCP or fentanyl in Perry's system and that the Fools Rush In star—who was candid about his struggles with addiction during his lifetime—was "reportedly clean for 19 months" at the time of his death.

But while authorities continue to investigate Perry's passing, his friends and family take comfort in memories and the time they spent with the actor—including his fellow Friends alum and onscreen wife Courteney Cox. 

"He visits me a lot, if we believe in that," the 59-year-old recently shared during the May 19 episode of CBS Sunday Morning. "I talk to my mom, my dad, Matthew. I feel like there are a lot of people that guide us. I sense Matthew's around for sure."

"I think he's probably one of the funniest human beings in the world," she continued. "He is genuinely a huge heart—obviously struggled. I'm so thankful I got to work so closely with him for so many years."

And of Perry, as well as her other Friends costars Jennifer Aniston, David Schwimmer, Lisa Kudrow and Matt LeBlanc, Courtney added, "That was my family. We went through everything. Those 10 years were everything."

And for more on how Perry's loved ones have celebrated all he was, keep reading. 

"He would love that the world is talking about how talented he was. And he really was very talented. As the Friends reunion was approaching, we rewatched the show together. 'F--k, I was so good!!!…See what I did there???' We rewound and studied scenes. Our respect and appreciation of humor is something that connected us. Being with him as he rediscovered his brilliance was magical. But, I obviously knew that man in a very different way, too. While I loved him deeper than I could comprehend, he was complicated, and he caused pain like I’d never known. No one in my adult life has had a more profound impact on me than Matthew Langford Perry. I have tremendous gratitude for that, for everything I learned from our relationship. I’d be remiss if I didn’t mention Al Anon, an invaluable resource for those who love someone struggling with this destructive disease. Matty, I feel relief that you are at peace.Sincerely,Moll-o-Rama(…fication)."

"We are all so utterly devastated by the loss of Matthew. We were more than just cast mates. We are a family. There is so much to say, but right now we're going to take a moment to grieve and process this unfathomable loss. In time we will say more, as and when we are able. For now, our thoughts and our love are with Matty's family, his friends, and everyone who loved him around the world."

"Matthew Perry made me laugh. Hard. You have not lived until you havewitnessed one of his in-between-the-takes confidential riffs on the absurdity of show business and the idiocy of male confidence, wrapped up perfectly with the sudden realization that we were both grown men who wear makeup for a living. Without substances, Matt had a huge, open heart and a pyrotechnical, joyous brain. I think the most beautiful parts of Matt made him the most vulnerable to the monster that he would have to fight for the rest of his life. His battle was heroic. They don’t have award shows for that. They should. Matt was full of contradictions. He was hilariously self deprecating and insecure and wildly self confident. He was a fountain of light with a huge capacity for darkness. He was profoundly blessed and terribly cursed.I want his parents to know that Matt was kind. Not just to his costar. To everyone. To honor Matt, I hope we can continue the work that mattered most to him: to open our hearts to so many who share his vulnerabilities, to encourage them to get the help they need, and to give them the love and the support they deserve. I’m so grateful that I had the opportunity to work with Matt, to spend some precious time with him, and most of all, to be his friend."

"I feel so unbelievably lucky to have been able to make that reunion show with six truly remarkable people, witnessing their precious unbreakable bond with each other. Spending time with Matthew was simply a dream come true. Kind, caring… and a comedic genius."

"I met Matthew Perry in 1993 at the Williamstown Theater Festival in Massachusetts," Gwyneth Paltrow wrote in a tribute on Instagram. "We were both there for most of the summer doing plays. He was so funny and so sweet and so much fun to be with. We drove out to swim in creeks, had beers in the local college bar, kissed in a field of long grass. It was a magical summer. He had shot the pilot of Friends but it had not aired yet. He was nervous, hoping his big break was just around the corner. It was. We stayed friends for a while until we drifted apart, but I was always happy to see him when I did. I am super sad today, as so many of us are. I hope Matthew is at peace at long last. I really do."

During Adele's Oct. 28 concert in Las Vegas, which took place just hours after Matthew's death was confirmed, she paused her show to honor him, recalling the impact he had on her childhood. "One of my friends, Andrew, when I was 12 did the best Chandler impression," she told the crowd. "And he would do it all the time to make us laugh. And if anyone was having a bad day or feeling low, he would just pretend to be Chandler. And I'll remember that character for the rest of my life." 

Maggie Wheeler, who played one of Perry's most memorable love interests on Friends, wrote on Instagram, "What a loss.The world will miss you Matthew Perry . The joy you brought to so many in your too short lifetime will live on. I feel so very blessed by every creative moment we shared." 

After his passing, Perry's Fools Rush In costar Salma Hayek noted it took a "couple of days to process this profound sadness."

"There is a special bond that happens when you share dreams with someone, and together you work towards them," she wrote in an Oct. 30 Instagram post. "I was very moved last year when Matthew shared on his Instagram stories how much he loved 'Fools Rush In,' and how he thought that that film we did together was probably his best movie."

"Throughout the years, he and I found ourselves reminiscing about that meaningful time in our lives with a deep sense of nostalgia and gratitude," she continued. "My friend, you are gone much too soon, but I will continue to cherish your silliness, your perseverance, and your lovely heart. Farewell, sweet Matthew, we will never forget you."

Alongside her final texts with Matthew days before his death, his former costar Ione Skye wrote on Instagram, "My last exchange a week ago. I’m very very sad. Loved this guy."

Kathleen Turner, who played Chandler Bing's parent on Friends, told People, "He had a good sense of humor and a good heart. He liked other people, which, to me, is terribly important, especially for an actor." 

The Beverly Hills, 90210 star remembered her time spent with the Emmy nominee.

"Matt always had THAT sense of humor," she wrote on Instagram. "Matt and I had a date and it was on Valentine's Day. He wanted to get a reservation at a restaurant in Malibu but couldn't so my dad got the reservation for him. We went and he talked about my dads Irish persuasiveness the majority of the night. Our friendship spanned a long time. A lifetime really. I know many are hurting, especially our little gang. He will be missed by many and definitely by us. Yes. I could be more poetic or say things better but right now, shock and sadness prevail."

Morgan Fairchild, who played Chandler Bing's mother on Friends, paid tribute to her onscreen son, captioning a social media post, "I'm heartbroken about the untimely death of my ‘son'. The loss of such a brilliant young actor is a shock. I'm sending love & condolences to his friends & family, especially his dad, John Bennett Perry, who I worked with on Flamingo Road & Falcon Crest."

The Whole Nine Yards actress, who worked alongside dad Bruce Willis and Perry during the 2000 film, shared a touching tribute after Perry's passing.

"I'm so sad to hear about Matthew Perry passing," she captioned an Instagram post. "When I was a kid and I was on set while he and my dad were doing whole nine and whole 10 yards he was so kind and funny and sweet with my sisters and me and I think his physical comedy and that movie still makes me laugh so much, I know he had many challenges in his life and brought a lot of joy to people with his comedy I hope he can rest peacefully." 

Paget Brewster, who played the role of Kathy in the fourth season of Friends, remembered the time spent alongside the actor on set.

"I'm so very sad to hear about @MatthewPerry," she wrote on X. "He was lovely to me on Friends and every time I saw him in the decades after. Please read his book. It was his legacy to help. He won't rest in peace though.. He's already too busy making everyone laugh up there."

Perry's Odd Couple costar reflected on his legacy, sharing a statement to social media.

"Our #OddCouple family suffered a great loss today," she wrote on X, alongside a photo featuring the cast. "The entire entertainment world has. I am too sad about the news to say more than this: @mattyperry4 was a sweetheart who deserved more peace in this life. 54 is too young to go. We love you, Matty! #RIPMatthewPerry."

The Violet star praised the actor for opening up about his sobriety journey after his passing.

"He struggled so much with addiction and was brave enough to be open and honest about it," Olivia Munn wrote on Instagram Story Oct. 28. "I'm so sorry to his family and friends who are getting this news today. Nothing short of heartbreaking."