The New York businessman who is believed to own the Montauk yacht where swimwear designer Martha Nolan was found dead on Aug. 5 was once accused of fighting and biting a former FDNY member at a tribute concert commemorating 20 years after the 9/11 terror attacks, according to a Manhattan lawsuit.Christopher Durnan, a 60-year-old businessman said to be an investor in Nolan's East x East brand, has owned a number of large pleasure boats and yachts over the years, public records show. Several of them have been named "Ripple" the same name used on the boat where police found Nolan dead at the scene.Durnan has not been charged with a crime or accused of wrongdoing in connection with Nolan's death.Former firefighter Michael Balfe accused Durnan of "viciously" attacking, biting and assaulting him at a Sept. 11, 2021 concert at Webster Hall in New York City. The lawsuit alleged that Balfe suffered serious injuries, both physically and mentally. The allegedly unprovoked attack caused permanent injuries, according to the lawsuit. Balfe also accused the venue of failing to maintain proper security.HOMICIDE INVESTIGATOR WARNS AGAINST RUSHING BIKINI DESIGNER'S YACHT DEATH PROBE AS LAWYER REVEALS NEW DETAILS"Plaintiff, MICHAEL BALFE, was injured; rendered sick, sore, lame and disabled; caused to undergo hospital and medical treatment and advice; unable to pursue his usual and regular activities; caused to undergo great conscious pain and suffering, continues to undergo such, and will permanently be affected by the injuries incurred as a result of the occurrence," the lawsuit alleged.The lawsuit was reported earlier by the New York Post, which identified Balfe as a Ground Zero first responder and Durnan as the owner of multiple boats docked in Montauk, including the Sea Ray 540, where Nolan was declared dead.MYSTERY STILL SURROUNDS DEATH OF IRISH FASHION DESIGNER AT EXCLUSIVE MONTAUK YACHT CLUBRead the civil complaint:Durnan's lawyers denied all the allegations, claimed self-defense and accused Balfe of being the aggressor.Police initially charged Durnan with four misdemeanors and a violation including assault and criminal possession of a controlled substance, court records show. He later pleaded guilty to a reduced charge of disorderly conduct and spent a year on conditional release after paying a $95 fine.Eventually, the parties reached an out-of-court settlement, according to court documents.A phone number listed for Durnan was out of service on Friday morning. His attorney in the Balfe case declined to comment.MONTAUK YACHT DEATH: TIMELINE REVEALS BIKINI MOGULS FINAL DAYS IN HAMPTONS BEFORE MYSTERIOUS DEMISEBalfe's lawyer, Darren Moore, told the Post his client would not be commenting out of respect for Nolan's family.Both a preliminary scene investigation and subsequent autopsy could not determine Nolan's cause of death, according to authorities. A toxicology report is pending and could provide more answers.Arthur Aidala, a prominent New York attorney retained by Nolan's family, told Fox News Digital earlier this week that reporting that she may have died from a drug overdose was premature speculation.CLICK HERE TO GET THE FOX NEWS APP"The cause of Marthas death is inconclusive and any reporting otherwise is mere speculation and irresponsible," he said. "The family asks that you respect their privacy during this devastating tragedy. We are focused on honoring Marthas legacy."Homicide detectives with the Suffolk County Police Department are investigating.