Busted L.I. DA quits Fri.

THE SUFFOLK County district attorney, accused by the feds of obstructing a probe into a beating by a police chief, is resigning at the end of the week.

When DA Thomas Spota was indicted last month for trying to cover up the pummeling, he said he’d be leaving office “at the earliest opportunity.”

Spota’s office announced Wednesday that he is stepping down Friday after more than 15 years in the position.

Emily Constant, Spota’s top deputy, will become the acting district attorney, according to an office spokesman.

Brooklyn federal prosecutors say Spota, 76, tried to scuttle a federal grand jury looking into county police Chief James Burke’s 2012 beating of a burglar who stole a bag full of the top cop’s sex toys.

Spota’s lawyers say he didn’t break any laws.

Christopher McPartland, the DA’s lead corruption prosecutor, was also charged in the case. McPartland, 51, “was reassigned to administrative duties unrelated to his former supervisory role,” a spokesman said.