More than three months after a Manhattan fashion designer was found dead on a boat at a ritzy Long Island yacht club, police still have no answers about the 33-year-old’s cause of death.

Suffolk County police previously stated that they believe Martha Nolan-O’Slatarra most likely died of an overdose after her unresponsive body was discovered on a boat moored at Montauk Yacht Club in early August, citing that there were “no signs of violence” and a white powdery substance was found nearby.

Police have so far refused to release any details on how she died or what that substance was — even denying The Post’s legal request for public documents related to her autopsy and toxicology reports, claiming they are “restricted to specific entities.” 

Police have yet to determine the cause of death for 33-year-old NYC fashion designer Martha Nolan-O’Slatarra. Nolan/memorial

“It’s frustrating,” Nolan-O’Slatarra’s family’s attorney, Arthur L. Aidala told The Post, adding the family has not seen a full toxicology report nor been given a final cause of death. 

“But we know the effort is being made by the DA’s office to do what needs to be done to cross every ‘t’ and dot every ‘i’ to get to the bottom of this,” he added. 

Aidala also pushed back against speculation that the Irish designer had died of an overdose and insisted she wasn’t known to do drugs. 

“Something doesn’t make sense here,” Aidala charged.

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“But we’re hanging back and letting law enforcement do their job.”

Police have so far only released limited details about Nolan-O’Slatarra’s final hours, leaving key questions about what unfolded that night unanswered.

Nolan-O’Slatarra was found dead on a boat at the Montauk Yacht Club on August 5th. VSCO/marthanolan

She was found unresponsive on a boat named “The Ripple” that was docked at the posh yacht club on Aug. 5, according to the Suffolk County Police Department — after residents nearby reported hearing screams late that night.

That boat belonged to Chris Durnan, 60, who is well-known locally and who owns another boat, “Hell In A Bucket,” which is moored at the same dock, according to public records. 

The night that Nolan-O’Slatarra died, she was at the swanky yacht club for a meeting with Durnan, who owns a 13% stake in her swimwear fashion company East x East, to discuss the expansion of her swimwear brand, according to New York Magazine.

Police have claimed there were “no signs of violence” despite a white powdery substance found nearby, along with The Post’s legal request to access public documents related to her autopsy was denied.

“If you guys are looking for more money, let’s sit down and talk about it,” Durnan wrote in a text to Nolan-O’Slatarra and her business partner Dylan Grace, according to messages obtained by the outlet.

Durnan was later found running around the yacht club naked, yelling and throwing sunscreen at other boats, attempting to get their attention.

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He owns and operates an insurance company called the Durnan Group, located in Rockville Centre.

He has not responded to The Post’s numerous requests for comment.

The Post has appealed the county’s denial to hand over the autopsy and toxicology records.