One of seven Long Island teens accused in the fatal hate-crime stabbing of a Hispanic immigrant has agreed to testify against his friends.

Nicholas Hausch, 18, yesterday in Suffolk County Court entered a guilty plea to gang-assault and hate-crime charges. Like his co-defendants, he had pleaded not guilty. He’d been facing five to 25 years in prison, but that could change now that’s he cooperating with the prosecution.

Cops say the thugs were driving around Patchogue looking for Hispanics to jump on Nov. 8, 2008, when they spotted Marcelo Lucero, 37, walking with a friend near the train station. Lucero, a native of Ecuador, fought back with his belt as his friend ran for his life. Jeffrey Conroy, 18, allegedly plunged a knife into Lucero’s chest and faces a second-degree-murder charge.

Since the slaying, a Justice Department probe of hate crimes on Eastern Long Island focused on police response and the Southern Poverty Law Center found “a pervasive climate of fear in the Latino community” of Suffolk County and cataloged a litany of anti-immigrant attacks dating back a decade.