STATEN ISLAND, N.Y. -- A Prince's Bay man was indicted Monday on manslaughter charges stemming from the death eight months ago of a bicyclist struck by a boat the defendant was allegedly towing on a trailer along Hylan Boulevard in Bay Terrace.

Michael Khmil, 42, of Foster Road, pleaded not guilty at his arraignment in state Supreme Court, St. George, to second-degree manslaughter, criminally negligent homicide and other charges in connection with Alexa Cioffi's death on Sept. 14.

Prosecutors allege the boat Khmil was towing was too heavy for the trailer and SUV transporting it, and the defendant failed to secure the trailer to his vehicle with chains.

Prosecutors said Cioffi, 21, of Eltingville, was fatally struck as she and a friend, Briana Emanuele, 22, of Prince's Bay, were riding their bikes on Hylan Boulevard northbound toward New Dorp.

A police investigation determined Khmil was driving a 2015 Toyota SUV northbound on Hylan with a boat in tow during the evening rush hour around 5 p.m.

Near Redgrave Avenue, the SUV attempted to change from the right lane to the center lane while overtaking the two bicyclists in the right lane.

As the SUV switched lanes, its trailer became detached and continued to travel north into the right lane, striking Emanuele, said police. The boat was propelled north, hitting Cioffi who became pinned, said police. The driver remained on the scene.

Both victims were unconscious and unresponsive when first responders arrived. Both women were taken to Staten Island University Hospital, Ocean Breeze, where Cioffi was pronounced dead.

Cioffi and Emanuele were riding to meet with Cioffi's sister, Jillian, 27, and some of their friends on their bicycles.

Cioffi graduated from Tottenville High School in 2013, according to Advance archives.

According to the indictment, Khmil's SUV was pulling a boat trailer with a maximum hauling capacity of 3,000 pounds, yet the boat weighed in excess of 4,000 pounds.

Khmil failed to secure the trailer to his SUV with chains and also failed to install a braking system on the trailer as prescribed by warning labels affixed to the trailer, contends the indictment.

As a result, the trailer detached from Khmil's SUV and struck Cioffi and Emanuele while traveling at a speed exceeding 20 miles per hour, the indictment alleges.

Besides the felony counts of manslaughter and criminally negligent homicide, Khmil is charged with misdemeanor counts of assault and reckless endangerment.

Second-degree manslaughter carries a maximum penalty of five to 15 years in prison on a trial conviction.

A tall, gray-haired man garbed in a gray hooded sweatshirt and blue sweatpants with vertical white stripes on the sides, Khmil made no statement during the brief proceeding.

Assistant District Attorney Mark Palladino said this case represents Khmil's first contact with the law, and he voluntarily surrendered to authorities Monday.

Khmil was released on his own recognizance and ordered back to court on May 24 for a conference.

He left court quickly with his lawyer Oleh N. Dekajlo.

Dekajlo could not immediately be reached for comment.

About 10 of Cioffi's friends and family members attended the proceeding.

Afterward, several of them wiped away tears in the hallway. They politely declined comment.