The state Assembly has launched a probe to determine whether a Republican member-elect fulfilled a legally mandated residency requirement to run for a Brooklyn district seat.

Assembly Speaker Carl Heastie said Thursday he’s directed the body’s judiciary committee to determine whether Assemblymember-elect Lester Chang lived in Brooklyn for at least a year. Chang won the seat for the 49th District, covering Dyker Heights and Bensonhurst, in the November election, defeating longtime Democratic incumbent Peter Abbate Jr.

The investigation — which could shake up representation for the district's 136,000 residents — marks a rare instance in which a member-elect’s residency has been officially investigated by the body. In a statement, Heastie said the probe was based on questions he called “credible.”

“We have an obligation to ensure that all members adhere to these constitutional residency requirements,” Heastie wrote in a statement, adding that the work must be completed by the end of the month.

If Chang, who previously ran for a Manhattan Assembly seat, can’t show proof he has lived in the borough for at least a year, then the Assembly might not seat him next month when the state Legislature convenes in its next session. Gov. Kathy Hochul would then be required to call a special election.

The probe can also trigger a lack of representation for the district for several weeks should Chang be removed.

Chang did not return a request for comment.

By state law, a person seeking to run for a state legislative seat must live in the district they seek to represent for at least a year. But the rules were more lenient this year because of the redistricting process, allowing candidates to simply live in the borough that includes the district they seek to represent.

According to NY1, questions on Chang’s residency first surfaced in September when the Asian Wave Alliance political club asked about his residency but were never shown proof. Abbate told the station Chang was registered to vote in Manhattan during the November 2021 election.

This story has been updated.