A Long Island homeowner’s summer kick-off took a horrifying turn Sunday evening after lifting the pool cover in their East Shoreham backyard — discovering a body that police are reportedly investigating as possibly being fugitive murder suspect Matthew Zoll.

Sources said Suffolk County police are now looking to confirm the body as the suspected 23-year-old killer and investigate the cause of death, according to Newsday.

Officials wouldn’t confirm whether this is their leading theory, but said the Homicide Squad is actively investigating and that the Medical Examiner’s office is performing an autopsy to determine the cause of death and confirm the victim’s identity.

“We can’t speculate any specific identity,” Suffolk cops told The Post.

Zoll, who is reportedly schizophrenic, is the main suspect of a November murder where he allegedly stabbed his 61-year-old dad, postal worker Joseph Zoll, to death inside their home in Rocky Point.

He then frantically fled the home, crashing his car on the William Floyd Parkway about 10 minutes after the alleged killing — leaving the totaled car and escaping on foot.

US Marshals spent several days scouring the wooded areas off the parkway, including the 1,600-acre Brookhaven State Park, in an intense search for Zoll following the deadly crash — but ultimately came up short.

The backyard where the body was found borders a wooded lot that runs behind four homes and leads straight to William Floyd Parkway.

Sources claim cops now believe Zoll may have traveled about a half-a-mile to the backyard, where he could’ve tried hiding underneath the winter pool cover before dying of various causes including drowning, hypothermia, suffocation, and more, Newsday said.